Volvo 240 Mods & Fixes
Just a few cool mods to keep you sane and properly entertained.

     UPDATED: April 20, 2017                       CONTACT       
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N  A  V  I  G  A  T  E     T  H  I  S     P  A  G  E
240 Hydraulic Clutch
240 Driving Light Brackets
240 Cup Holder Project G80 Diff in your 240
Fixing Underhood Grounds Benefits of Anti-Corrosive Paste Fix or Hardwire Your 240 Taillights Lowering Your 240
The 240 Headlight Step Relay Step Relay ELIMINATION Mods using Relays
240 Tach Install
Electric Cooling Fans Speedo Recalibration Komfort Blinker Upgrade
240 Small Tach
Fuel Pump Relay Mod Bulb Fail Sensor Part 1 M46 OD Harness
Driver Door Bad Lock Wires
Later Windshield in your 240 Bulb Fail Sensor Part 2 Auto Trans Harness
Temp Compensation Board
Faster Wipers Bulb Fail Sensor Part 3
M46/M47 Shift Knob Fix

Headlight Relay Harness
In-Tank Pump Upgrade

I like 240s a lot and there's nothing I like better than modifying them for performance,
handling, comfort, etc.  In this page I will try to outline some cool mods I have done to my 240s.
Your comments are welcome:

Hydraulic Clutch Information for your 240
Back in 2011 I got tired of stretching and snapping clutch cables, so I installed hydraulics for the clutch.  I recently created a web page to help keep track of the parts and information.  Here it is below:

Mounting Driving Lights on your 240 without Drilling your Bumper!
If you're one that likes the look or function of killer driving lights on your 240, but don't want holes in the top of your bumper, I'm here to show you an alternative to drilling holes in your bumper. 

The first two photos to the left show 240s with holes drilled in their bumpers.  The 3rd, 4th and 5th photos are what I found in some old Volvo optional accessory literature.  It turns out that Volvo actually produced brackets that mounted behind the bumper and then came through the bottom of the grill.  The last photo offers a good view of this bracket.  While it will be impossible to actually locate an original bracket, I think making them would not be all that hard to do.  Just make sure you use fairly thick steel so the lights don't bounce from bracket flex.

Making a Custom Cup Holder for your 240
We all know our beloved 240s never came with cup holders. There have been a number of cup holder projects in the internet over the years.  When I saw this one in the Turbobricks forum, I felt it really needed to be shown.  The thoughtful design allows it to be securely anchored over the e-brake handle, using the e-brake handle button to help pin the front against the shifter hump.  It's a nice design feature to keep in mind when you build (or adapt) such a thing for your car. 
See more photos and dimensions here:

Installing a G80 Locking Differential from a 700/900 in your 240
The G80 Locking Differential is a special differential that Volvo began putting in the 740/940 model rear ends beginning about 1992.  It was manufactured by Eaton. This differential is designed to provide positive locking of the rear wheels during low speeds (typically under 25 mph).  As speed increases, the differential can sense the speed change and it unlocks for speeds typically above 25 mph.  It does this by way of a centifical weight that changes position as speed increases.

240 owners have discovered that this differential is a (nearly) simple direct bolt-in to the 240 Dana 1031 and 1041 rear ends.  In many cases, these differentials will bolt in and run fine with no adjustments, usually even without replacement of any bearings, shims or gears.  There are some that will tell you that the "correct" way is to fit the unit just as you would any new differential replacement, using a professional technician.  The choice is yours, however many "junkyard" DIY mechanics have already done it successfully

In all cases when fitting this differential to a 240 rear end, you will need to trim a small amount of steel off the inner end of the right side axle.  This is because the right axle will not fit all the way in with the G80 in place. That's the only part that is not a direct bolt-in. The trim amount is about 1/4 inch. 
It's also common for modifications to be made to the G80 to alter the locking to un-locking transition speed to make it stay locked  later, unlocking at a higher speed, or to even stay locked at all speeds.  This is done by a couple different methods and these are outlined in the attached links below. Not all of the methods are the same, so if this parts interests you, read it all. 

Fixing Common Corroded Ground Points (and power connections) Under Your Hood
I hear about strange intermittent electrical problems from frustrated 240 owners nearly every day. These problems occur because . . . .  #1: These cars are old and . . . .   #2: Electrical connections tend to slowly corrode over time and . . . #3: Cars that spend most of their lives outdoors always suffer more corrosion in electrical connection points.  Spending a little time cleaning connections can go a long way in keeping your 240 running well, especially if your car has lived outdoors in the weather for many years (that's really bad for long electrical life for any car). 
WATCH THIS VIDEO (also read the comments section):

And on a related note . . . . .
If I have not yet fully stressed the importance of clean and tight electrical connections, I will do it again. If we can just just keep our connections clean and tight, almost all of the electrical issues would be history forever.  That would be nice, right?

I have owned a number of Volvos over the last 30 years and my current 240 is way over 30 years old. It almost never has electrical problems. Nothing like the endless numbers of other 240s out there that I hear about almost every day by email. What's the difference you ask?  The difference is that my 240 has been alway garaged all of its life.  Why is that important?  Because leaving any car out in the open elements for years and years slowing introduces corrosion to grounds and power connections until things begin to go wrong. 
So if you own one of those cars that has been outside forever, it's not too late. You can still clean as many grounds and electrical connections as possible.  And while you're at it, smear a little anti-corrosive paste on those connections.  Read more about that below.
Dave Barton

The below information was contributed by Ron Kwas and should come in very handy to old Volvo owners:
Anit-Corrosive Zinc Paste (a generic name for zinc dust contained in grease) was originally developed for and required by electrical codes for use on alumunum to copper electrical connections (or other dissimilar metal connections).  No, it's not anything like Dielectric Grease, which is often incorrectly recommended. Dielectric Grease can buy some protection in the form of encapsulation from moisture, but it also carries with it the potential disadvantage of locking in moisture or corrosion which may have already started.  Anti-Corrosive Zinc Paste (or ACZP) is the next evolution of the encapsulation principle, because zinc (lowest on the Galvanic nobility chart) neutralizes corrosion on a micro-scale to truly protect connections on a long-term basis using that encapsulation, INCLUDING an added protection from corrosion which may want to start under there. 

Ron has used for years and recommends Penetrox A (by Burndy). It's easily available on line. Ron has studied the effects and downsides of other manufacturer's versions and has found some to be unsuitable.  He is a huge advocate of treating ALL electrical connections on our cars (except of course High Voltage Ignition connections) with a suitable version of this material. 

You can learn a lot more about this stuff at Ron's page here: 

Hardwiring your 240 Taillights (Tail Lamps)
I get a pretty fair number of emails about failing tail lamps in 240s, so I decided to compile some info about that here.  This applies to 240 sedans with large 6-panel tail lights only, since wagons and early sedans with smaller 5-panel tail lights don't have the fragile circuit boards on the backside. Most people with these tail lamps know what it's like to have bulbs stop working due to connection issues between the bulb holder and the circuit board conductor. It can be frustrating. Hardwiring them sounds like a big deal, but it's not hard at all. It means you will be tossing out your old circuit boards and then attaching wires (with crimp connectors) directly to the contacts on your bulb holders.

Certainly you can just buy new circuit boards on the internet (like the below left pic), but those will just fail again. My advice to anyone having such bulb problems, do the hardwire
project, enjoy your perfect taillights and never look back.  If you're completely inept at mechanical and wiring issues, find someone who can help.
Having taillights that ALWAYS WORK when they're supposed to is absolutely worth the effort.

I won't go into great detail here about the procedures because there are several good sites listed below on this subject. I just want to cover a couple things from my own
experiences. There are two options you have when attaching wires directly to bulb holders; 1. Soldering them.  2. Using crimp female spade terminals.  My preference is using crimp terminals, because it makes it less likely that connections will break when changing bulbs. This method will require you to trim the metal contacts slightly if you use .250 inch (6.3 mm) terminals, since the contacts will be a bit too wide.  Trimming these contacts can be done with sheet metal snips.  Or you can just use larger female crimp terminals.  It turns out that .312 inch (7.9 mm) female crimp terminals fit perfectly onto the bulb holder tabs. These are availble cheap in my Harness Parts Page.  You can use straight or flag (90 degree) .312 inch terminals. It doesn't matter, except the flag terminals are a bit harder to crimp.

The hardest part about this project is figuring out what wires go to which terminal on which bulb holder. My advice it to start drawing diagrams of the wire colors going to the tail lights and use a test light to trace those colors to each bulb holder and each terminal on those bulb holders. Then figure out which tab on each bulb holder should receive each wire. Keep in mind that some bulbs and holders have two hots and a ground for a total of three circuits. 1981-85 240s with 6-panel lights will have different circuits than 1986-93 cars. Helpful free on-line Volvo wiring diagrams are available at


Quick Fix to get your 240 Taillight Bulbs to Work Again (using aluminum foil).
If you have the above circuit board issues and don't have the time or patience to hard wire your bulbs (above), here's a quick fix. Thank you to Michael Yount for offering this solution.
Simply cut some small pieces of aluminum foil and place them on your circuit boards as shown in the photos.  Use some hobby tacky glue to keep them in place.  They will help bridge the bulb holder circuit if you have worn out circuit boards.

Lowering Your 240
Should you change the ride height of your 240?  That's a question that comes along often enough.  You have to decide if you like your car at the original ride height (cause you drive in floods?) or if it looks better to you a little lower.  Sometimes the road conditions in your area will help you decide, since lowering a car means a more firm ride and less undercar clearance.  If you decide you want to lower it, here are some options to consider. 

Sport Springs:  Most sport springs that are available (iPd Sport Lowering Springs being the most popular brand) will lower your 240 about 1.5 to 2 inches.  Other spring companies offering 240 springs: B & G Suspension, King Springs (Australia)
The ride will be a little stiffer, but it will be very important to use good struts and shocks that will be able to control a stiffer spring.  Bilstein HD shocks or Koni adjustable shocks are a pretty good match to this type of spring.  

Adjustable Coil Suspension (Coil-overs):  These are nice if you can find them. They offer a wider range of adjustability allowing the use of a variety of coil stiffness and adjustable ride heights. Occasionally there are people who produce kits in small quantities for 240s.  Usually not though.  If you're handy, you can build your own set.  Here are some good articles: 240 Coilovers: The Kyote WayDIY 240 Series Coilover Instructions. Search the Turbobricks forum for more.

Cutting your Stock Springs:  There are people who will scream at you to never try this.  I think it's because there are more failures than great successes.  The key to getting it right is experience.  If you use the vast experience in the following thread, particularly from Tuff240, who has more experience than anyone I know, you will get where you want to go:  Cutting Volvo 240 Factory Springs.

Installing a Later Windshield in an early Volvo 240 or 140
This is a fairly common 240 mod with a fair amount of info already out there. But since I still get regular questions about this, I decided to post this guide. 

The 240 was built from 1974 (1975 model year) to 1993 and the body design changed very little over the 18 year production run.  The windshield structure had no changes whatsoever between 1974 and 1993.  Even in an earlier 140, the windshield structure is identical to the 240.  You may have noticed that all 1991-93 240s came with a different type of windshield trim than those found on earlier models.  It's all black and made of rubber. No metal trim is used like on earlier 240s.

1975-90 240 (and 140) windshield with metal trim:
  This early type of windshield was glued in place using a soft, messy butyl rubber. Plastic trim clips were inserted into the soft rubber to hold the metal trim in place.  This trim tended to stick up from the windshield too far and in many cases it created lots of wind noise.  Thanks go to Ben Buja for supplying this photo.

1991-93 240 windshield with integral rubber trim: 
As you can see, this later type black rubber trim is nearly flush with the body.  It's cleaner looking and can reduce nasty windnoise. This newer 1991+ windshield always comes with this new rubber trim already attached around the edge. The trim is NOT available separately. The installer will use a newer style urethane rubber when gluing it in, instead of the soft, messy butyl. 

Fitting a later windshield to an earlier 240 (or 140) is not a problem at all.  It goes right in with no difference in the installation.  Be aware that there are installers out there who aren't aware that the 240 never changed and they may be skeptical about doing this install on an earlier 240.  Some will even refuse to do such an install because they won't believe you.  But rest assured, the mewer windshield WILL fit.  Many 240 owners have had this done over the years. But if you want to avoid the argument, just tell the installer the car is a 1991, '92 or '93. 

Here's a great story from T.M. of White Marsh, Virginia:  "I took your advice about using a 1991 windshield in my 1987 240 Volvo. Just like you suggested, in your article, I told the installer I needed a 1991 windshield for my car. When I brought my car in to have my new glass installed the receptionist goes out and looks at my car's door ID tag and sees it's a 1987, she freaked out.  She was all like, "it won't fit", "I won't give you a warranty", and if I insist on putting this windshield in the car I would have to be responsible when it all went wrong.  I responded to this receptionist that, it would fit, it would be easier for the workers to install, it would look fine and that she already told me I wouldn't have a warranty anyway because she said I had rust in the channel, so what is the difference.  She got all huffy when I told the installers to proceed anyway and to ignore her protests.  She was in a bigger snit when she saw that it fit and it looked just fine too. The rust was NOT in the channel, but I did not really care about her silly warranty anyway."

"You were totally right, the wind noise was much less, and the installation was so much cleaner. I had to replace the old windshield with the old style seals, due to leaks, and I am glad I took your advice everything is great; not original, but actually better. One freaked out receptionist, two satisfied installers, one happy customer, and one slightly improved Volvo.  A good day was had by most of us anyway.  I do not think the receptionist is ever going to forgive me for "lying" to her and having it all work out just fine. lol."

<<<  Side note regarding 140 series back glass:  This photo was submitted by Johnny J. of Sparks, Nevada. His 1973 142 needed a new rear windshield, which was obsolete. So he took a chance on a rear glass from a 1990 244. The glass fits perfectly and wire connectors even line up perfectly for the defrost element. And the newer rubber seal from the 1990 glass went right in. So this shows that any 240 back glass will perfectly replace the back glass in a 140 series in case you need to know.

Build a Badass Headlight Harness using Relays
This is a good project for anyone with any older Volvo, especially if you have or want to to upgrade to brighter bulbs or headlights. 
For the best info I know, read Daniel Stern's page on this subject.  He also has several useful diagrams for designing and building your own relay harness.

Here are some Volvo specific diagrams that have been available on-line for many years. These use the same principles:

Unlocking the Mysteries of the 240 Headlight Step Relay.
Test Procedure.
These relays are rather special in that they have a latching function.  A latching function is where you can click and release a momentary button or switch (such as a high/low beam stalk) and the relay will lock (latch) in the on or off position until the stalk is pulled again. For this Volvo relay, one click latches it "ON" and another click latches it "OFF."  I have created the diagram PDF at the left for anyone who wants to better understand how these work.  I have also added a test procedure if you think you have a broken one.

How to Substitute Available Relays and Eliminate your Volvo 240 Headlight Step Relay
As original Volvo 240 headlight step relays become more expensive and less common, here is an alternative I have designed that you can create yourself and eliminate the Volvo 240 Step Relay if you want to. This method uses two readily available relays

<<< Click on image to the left for 2-page PDF.

You will need to locate two relays to complete this project:
1. A standard SPST mini relay (5 pole), and
2. A special latching relay known commonly as a VW Latching Headlight Relay. This is basically a copy of an old VW headlamp dip relay and they are used for a variety of things these days.  Cost is about $18-$25 on Amazon or eBay. Search for "VW latching headlight relay" or "LR35 relay".

I don't offer the latching relay here, but if you need a standard SPST relay, this one will do:

        Your feedback is requested if you decide to do this for your 240.
        CONTACT ME

240 Electric Speedometer Custom Re-Calibration
(Applies to 1986 and later 240 models. 700/900 models too)
This information has been compiled from discussion threads in Turbobricks, the Brickboard and from customer contibutions.  It's a simple mod, but some clarification was needed to make it simple for the rest of us. Using modern electronics, you may add a variable trimpot (rheostat) to alter or adjust the signal the speedometer receives from the speed sensor in the rear axle.

First thing you'll need to do is disassemble your instrument cluster and remove your speedometer.  If you don't know how, instructions for that can be found in my 240 Odometer Repair Page

<<< Depending on the year of your 240, you'll see a resistor like one of these two photos. That is the calibration resistor. It is static (or non-adjustable).  It was installed by Volvo to alter the speed signal for the specific speedometer they selected for your car.  The original resistor has been measured by others at around 51 to 56 ohms.  By changing the value of that resistor, you can change the signal received by the speedometer.  Some have installed different static resistors to reset their calibration. A few have installed variable resistors so the calibration can be fine tuned when driving.  That's what this article is about. 

1. Using a soldering iron, heat the solder behind the original resistor and remove it.  Simple task.

<<< 2. Next insert a stripped wire into each hole and solder them on the back so they're secure. You may use 18 to 22 gauge wire or smaller.  If the holes need to be opened up a little, use a small drill, then solder.

<<< 3. Here is an example of a 100 ohm variable resistor (adjustable between zero and 100 ohms). A "linear" type is preferred.  These can be found on eBay and are very cheap (usually made in China). Often they're offered in lots of 5 or 10 for under $10.  Feel free to put an ohm meter on it and find the two pins needed for the wire hookups.  Polarity is not important.  While you're at it, set it somewhere in the middle (50-55 ohms).

<<< A customer of mine sent this pic.  He mounted a variable resistor behind the hole formerly occupied by the clock adjuster.  This way he could tune it easily after the dash was assembled and it looks very clean.  There's no need to get this fancy if you don't want to. The resistor can also be put under the dash or anywhere within reach depending on wire length. 

If you can offer any new information or better ideas for this mod, please email.

Resources for more info:,,

Understanding and Dealing with a Volvo Bulb Failure Sensor, Part 1 of 3
The Bulb Failure Sensor (or Bulb Failure Relay) is a device found in 1978 and newer 240, 700, 900 models that alerts the driver of a failed low-beam headlamp, parking lamp, tail lamp or brake lamp by sensing the balance of current draw between the left and right side lighting circuits.  When that dash light comes on, it means the sensor recognizes that one side is drawing more current that the other.  This is supposed to means there is a bulb out, but sometimes it can be triggered by incorrect or mismatched bulbs, or even sometimes when one side has a newer bulb than the other.
Variations of this sensor:
Yellow case, PN 1362278 (1978-85 240 and 740 through 1985)
Black case, PN 1235271 (1978-85 240, other years probable, but details unknown)
Red case (pictured at left), PN 1362370, which fits the 1986-93 240, 1986 and later 740, 780, and 1991-94 940
Yellow case, PN 3545704, for 1988-90 760, 1991-94 940 SE and 960
Blue case, PN 9128814, also fitting 1988-90 760, 1991-94 940 SE and 960.

This information is taken from the best sources I have for USA and Canada models.  It may not correctly apply to all European or Australian models.  I have received information that there are some Australian models with a different red case sensor from above, which I have not yet identified.  If you can help with info and/or photos, please email.

#1 Recomendation: My best advice for those who are simply tired of seeing the bulb failure light come on when a bulb hasn't really failed is as follows:
Step 1:  Reach under the dash and find the offending bulb in the back of the instrument cluster.
Step 2:  Twist and remove.
Step 3:  Take it outside and throw it as far as you can.

Dealing with a Volvo Bulb Failure Sensor, Part 2 of 3
Making a "By-Pass" Sensor out of an old Bulb Failure Sensor

Sometimes the failure sensor can fail internally, rendering some of your lights inoperable.
This is becoming more common as they age.
FAILURE SYMPTOMS: The symptoms of failure can be headlights or tail lights (or sometimes just one whole side) that will not work even after verifying the fuses, switches, headlight relays and wiring are all in good order.

<<< Black Sensor 1235271: Referring to the diagram at left, for those of you who have had enough of the BLACK 1978-85 bulb failure sensor, here is a diagram showing the internal workings and instructions for bypassing or eliminating its function if needed.  Bypassing this sensor will eliminate the bulb failure light in your dash, but more importantly, it will eliminate the fragile circuits inside this sensor which can kill your low-beam headlamps, parking lamps, tail lamps and brake lamps if it fails.  Diagram view is from top of sensor or top face of plug.

<<< Yellow Sensor 1362278: Diagram at left is for the YELLOW 1978-85 bulb failure sensor (1978-85 240, 260 and 740)Diagram view is from top of sensor or top face of plug.

Red Sensor 1362370: Diagram at left is for the RED 1986-93 bulb failure sensor (
1986-93 240, 1986 and later 740, 780, and 1991-94 940).  Diagram view is from top of sensor or top face of plug.

Bypassing a Volvo Bulb Failure Sensor, Part 3 of 3
Making some simple bypass leads for a Quick and Easy Fix.
If you don't feel like modifying a Bulb Failure Sensor, there is a simpler way to bypass these circuits without using one.  And I don't mean to suggest cutting off the multi-pin plug and splicing wires together (which of course you can do if you like).  A better method, with no barbaric butchery, is to assemble some simple crimp terminals with a few short pieces of wire. Then insert them into the multi-pin connector, respective of the bypass diagrams shown above  As it turns out, the multi-pin connectors for these sensors use fairly common 3.5 mm bullet terminals. So all you need are some male bullets and wire. Coincidentally, the 3.5 mm male terminals and insulators are available cheap in my Harness Parts Page HERE.  In the photo at left, you can see how these should look. The configuration is different for some sensors, so pay attention to the diagrams above. 

Faster Windshield Wipers
This is a common complaint among 240 owners.  Here are some suggestions to make your life better.

<<< Referring the the diagram at left, this is a very simple mod I have done to my 240s.  By swapping two wires on your wiper switch (terminals 53 and 53b), you can reverese your wiper switch function. This means when your stalk is pushed to the first position, instead of the slow (crawl) speed, your wipers go to high-speed.  Slow speed becomes the second position instead of the first. This modification also makes it so your intermittent wipers run at high-speed.  This particular diagram is for a 1985 240.  I have noticed that on some other year diagrams the wire colors are reversed. Either way, terminals 53 and 53b are the ones to swap no matter what. Try it out.

Also remember your 240 is a pretty old car. Wire connections on older 240s can get corroded over time and have been known to loosen up sometimes.  As a point of maintenance, you should inspect electrical connections (and grounds) on occasion to make sure they look clean and tight. The harness plug going to your wiper motor under your hood has probably never been checked. Now is a good time to clean it.  Unplug it and have a look.  And keep this in mind . . . if you have ever find a melted plastic connector anywhere in your car, it's because of excess heat generated by high resistance from a poor connection. So good clean connections are important.

Lastly, use a volt meter to check the battery voltage while your engine is running.  Low voltage makes for slow wipers too.  Most 240s are lucky to put out 13.8 volts. Many will be lower and some have less than 13 volts.  That makes your wipers very, very sad.  Dirty, corroded or loose connections at the battery, starter and alternator can have a big effect here.  If you want to see higher battery voltage, clean the related connections, including grounds.  You might also consider an adjustable voltage regulator.  I like my 240s in the 14.2 to 14.5 volt range.  Adjustable voltage regulators are available HERE

If you have more serious issues with your windshield wipers, you might visit this Turbobricks thread:

Options and Experiments in the Installation of a Primary Electric Cooling Fan in your Volvo 240
When in good working order, the original belt driven viscous clutch fan in your 240 can handle most cooling needs.  But if you have been thinking that your 240 needs an electric primary cooling fan, here is a page I put together on my experiences with several electric fan conversions over the years, from small 14 inch GM fans to big Ford or Lincoln Mark VIII fans.  Plus a variety of wiring diagrams are included for building your own relay fan controllers systems.

Or CLICK HERE for my 4-Speed Fan Controller Project Page (for my big Lincoln Mark VIII fan).

Modifying your Volvo using Relays
 I'm putting this here because having an understanding of simple relay functions can help so much for your car projects.  Many of the suggestions in this modification page rely on relays.  Not too many years ago my relay knowledge was limited to installing a pair of fogs lights.  The internet has helped a lot in this area and most of you can now be really successful with relays by using the resources available. 

The below Relay Guide is not Volvo specific, but it's a great resource for expanding your general auto relay knowlege.  (3.3mb PDF)

Here is another page with more relay configurations (some similar):  <<< And this is the best site I know for improving your auto lighting with added relays.

If you know any any other useful resources that would be a good fit here, please email me. 

Turn Signal (Blinker) 3-Flash Upgrade using VW/Audi Komfort Blinker Relay
Several years ago I drove a late model BMW M5 (E60) and fell in love with the Comfort Blinker (or "Komfort Blinker") that the Germans were putting into their cars.  This feature allows you to momentarily tap the turn signal stalk left or right and you get three flashes from your blinkers.  Ok, for those of you who aren't so lazy, I guess you can just pull and hold the stalk for three flashes every time you change lanes or pass.  But I just simply likde this feature enough that in 2010 I decided to make it a possibility for my 240. 

I suspected this feature in the late model BMW might be controlled by a central computer. No matter.... as it turns out, Volkswagen and Audi have been making this feature available in some of their cars since about 2006.  The module they use is a special relay, VW or Audi PN 000 953 227A.  After obtaining one of these relays on-line (cost was about $60 shipped from Germany), I set out to discover how it functioned and if it could be wired into the existing 240 blinker circuit.  This took some studying and experimentation, but I was successful.  Installing this relay into a 240 makes the blinkers work exactly the same way as the BMW, VW or Audi.  Also, it does not affect the normal operation of the blinkers cancelling automatically after a turn or with the emergency 4-way flashers. A pleasant surprise I also discovered was that in addition to getting 3 flashes when you momentarily tap the lever, if you hold it for about 1/2 second you get 4 flashes.  I don't know if that's also an intended feature in VW/Audi cars, but it works great in a Volvo.

I created a diagram (linked below or click image) for those of you who want to do this in your own Volvo. The VW/Audi relay has five poles, same layout as any standard 5-pole power relay and connecting it to the blinker system is as simple as splicing four wires at the flasher switch and connecting one ground.  I believe this operation would also be successful in any Volvo 700 or 900 series, or in any car (probably any European car) that uses
an emergency flasher switch and a blinker flasher relay similar to the Hella 3-pole flasher relay used in these Volvos. 

Completed 2010. Check the diagram and see for yourself.

I also did this mod on my brother's 1988 BMW M5 (E28) and it was successful.  Diagram below.

240 M46 Overdrive Wire Harness Design, Construction, Mods
A few years ago after the auto transmission went south in my 242 Turbo 120 miles from home (Thank you AAA for your extended towing coverage), I swore off autos and decided to fit an M46 (4-speed plus OD).  I'm not going into the fitting of an M46, but I am going to reveal the secrets of the M46 wire harness that you'll need if you ever do this in your 240.  When I began working on the swap, I found an old M46 harness in a junk yard 240.  It was in really bad condition, so I used it to construct a new one.  The PDF diagrams here are the result of my research.  Using these diagrams, you can make your own harness from scratch like I did, using a few salvage yard 240 parts, some common connectors and some wire.  If your car had an auto trans, you'll need to add a terminal in the round multipin connector on the back of your instrument cluster for the "OD" indicator light.  There will be no terminal in that spot in an auto car.  And the 4th gear ground switch in the transmission uses a common female bullet found in many places under the hood of a Volvo.  This is the female bullet with the silicone sleeve.  If that can't be found, a 3.5 mm female bullet terminal works fine.

These diagrams will also show you the differences between the 1981-84 BLUE relay and the 1985 and later RED relay, so you may choose either harness design, since both harnesses and relays ultimately do exactly the same thing and will work on any M46 overdrive.  Or you may use these diagrams to convert from a BLUE relay to a RED relay or vice versa. 

As of September 2015 I now offer new M46 Wire Harnesses for all year 240s:  CLICK HERE to find them in my Harness Page.

240 Auto Transmission Overdrive Wire Harness Design and Construction
Since I did the above M46 diagrams I thought it would be good to illustrate how the 240 auto trans ORANGE and WHITE overdrive relays work.  There is almost no difference in the relay circuits between these two relays. They are essentially interchangeable, EXCEPT that the OD light on the dash seems to come on opposite of when it's supposed to when the other relay is installed.

Shifter Knob Fix (M46/M47) Manual Transmission
If you drive a Volvo with the M-46 or M-47 manual transmission, then you will likely already know (or you will) what it's like to have the shifter knob come off in your hand during a rapid 1-2 shift.  It's very annoying, especially when it yanks the wires off of your OD switch and you have to put things back together on the side of the road.  Here's a very simple cure.

First, pull off your shifter knob and if you have OD wires, tuck them off to the side and out of the way.  Get out your drill and start by drilling a hole in the knob just like you see in the photos.  Then continue the hole into the metal shifter tube.  The hole should be just slightly smaller than the screw you decide to use.  I used a countersink type screw, so I also drilled a shallow countersink hole in the knob.  I screwed the screw into the tube to test how tight it would be and decided the tip of the screw was a bit too long
, so I snipped it off.  I didn't want it to interfere with the wires.  The last photo shows the finished result.  That should fix it for good.

Upgrade the In-Tank Fuel Pump in your 240 with a 740 Turbo Pump
The Bosch in-tank fuel pump found in your 240 Turbo will be the same pump used in all 240/260 models from 1976 to 1984.  It's very small and while it will provide adequate fuel for a non-turbo Volvo, it has been considered by many to be too small for a turbo motor with any increased engine performance.  The Volvo part number for the original in-tank pump up to 1984 is 1276330.  In 1985, that part number changed to 3507436, which was used through 1993.  The 740 Turbo pump I used for this conversion, which was used from 1986 and later in 700 and 900 Turbo models, as well as 960 models, is PN 3517845.  This pump retails for between $150 and $200 new.  It is also widely available in salvage yards for a lot less, although you should be cautious, because some pumps found in salvage yards may be dead already.  For my 240 Turbo, I chose to install a used pump from a salvaged Volvo.  If you need to test a pump with a battery, do it very briefly... only a second.  These pumps are not designed to run dry and it can damage them quickly.
<<< The photos shown are from a 240 sedan trunk.  The wagon will be a little extra work getting to the top of the fuel tank, but otherwise it's the same. 
Begin by removing the access cover plate above the tank.
The two hoses shown here are the main feed line going to the main pump and the return line from the engine.  I have also included a photo showing these two fuel lines under the car. 
Main Feed Line: The original main fuel hose was a cloth braided type and it's normally secured with hose clamps on the tank exit assembly at the top of the tank and also at the main fuel pump under the car. When this type of hose gets old, it will usually begin to weep fuel. When weeping, it may begin so slowly that it only gets the outer cloth braid wet.  If you are noticing a fuel smell shortly after parking the car or you see any fuel dripping near the left rear tire, check this hose to see if fuel is weeping through.  Replace it if it's questionable, since it will only get worse with age.  The hose size is 12 mm if you need to replace it (about 4 feet is needed).  12 mm hose is common in Europe, but not so common in the USA.  7/16 inch fuel hose is a close substitute (it's best to choose high-pressure fuel injection hose), however even 7/16 inch is hard to find in auto parts stores in the USA.  Some people have used 3/8 inch hose, but I think it's too small and will be difficult to stretch onto the fittings.   Both 12mm and 7/16 inch fuel line are available on-line.
Return Line:  This line transitions from a metal line under the car to a flexible plastic line (covered with a rubber sheath) going to the top of the tank.  This line will rarely ever need to be replaced unless you damage it in this proceedure, but as you will discover if you do this type of work, it's very hard to manipulate this line when removing the pump assembly from the tank access hole. It does not disconnect from the pump assembly (unless you cut it off).  After doing this job a few times and finding how much it sucked, I now choose to cut it off.  When the plastic line is cut off of the end fittings on both ends, you'll see that the end fittings are just ordinary barbed nipple fittings and normal fuel line can then be secured on them with hose clamps.  The size for this line should be 8 mm (or 5/16 inch will work).  

<<< Main Feed Line again: Since in this instance, I was replacing the main fuel hose because it was old and beginning to weep, cutting it off the fitting was the easiest way to remove it.  Otherwise, this is a good time to disconnect this line.

<<< I like having the right tool for a job.  iPd sells this tool for turning the top retaining ring on the pump assembly to release it from the top of the tank.  If you don't have one, you can try using two large screwdrivers crossed over each other or the hammer and chisel method to tap the ring.  The retaining ring will need to turn about 1/8 turn to the left, or counter-clockwise.

<<< Before you can try lifting the pump assembly up and out of the tank, you must first disconnect the return line.  This is done under the car.  It's a simple flair fitting.  Use two open end wrenches (14 or 15 mm I think).

<<< Then you can slowly work the hose out toward the pump assembly.  I found that the hose needs to come up and out first.  Then you can gently lift out the pump assembly.  When you do this you will know why I chose to toss the original plastic return hose in the trash and use a normal fuel hose with a clamp instead.

<<< Here is the pump assembly out of the tank. 
Also, it will be a good idea to get a new pump filter sock.  See it in the photo?

<<< You can see the size difference between the two pumps. 

<<< If you need to remove the pump assembly from the trunk area to work on it elsewhere, pull up that plastic cover to the left and you'll find the power and ground connections there that you can disconnect.

<<< Remove the ring terminal from the old pump.  I think that size is 6 mm.
Also release the orange plastic band holding the pump.  Remove the hose clamps and the fuel hose and pump from the metal tube.

<<< Since the 740 Turbo pump is longer than the old one, the metal feed tube needs to be cut off.  You'll need to trim about 1.5 inches.  Carefully measure it yourself to be sure.  Keep in mind that the bottom of the new pump needs to be in the same position near the tank bottom as the old pump.  If you cut off a little too much of the metal tube, you can always just put a longer hose on.  It's not rocket science.

<<< CAUTION: If you found an "accordian" hose that looks like this, DO NOT reuse it. 
It's a weak hose and will rupture with age (if it hasn't already).

Here's the final product. 
When you re-insert the pump assembly back into the tank, be very careful to avoid damaging the wires. 

More info on the subject of 240 in-tank pumps and related parts may be found here:

If you know of any helpful hints not mentioned here, please write me.
Thanks,  Dave

Add a Secondary Relay to take the Load off your 240 Fuel Pump Relay
The fuel pump relay in your 240 takes a lot of abuse and it's expected to run your fuel pumps for years and years without fail.  Well fail they do, usually because of unwanted heat after years of use.  
They often run hot because; 1. They handle a heavy load. 2. The heat causes their plug connections to develop higher resistance, which then causes more heat, which makes failure occur even faster. 

Below I have outlined how I added a standard 4-pin relay (or 5-pin will work too) to handle the pump loads, giving the original pump relay a much welcomed rest.  The new added relay can be any standard 4 or 5 pin type relay with a load rating of 15 amps or higher,
such as the ones I offer in my relay page here:
What this does is take the heavy load off of the expensive Volvo relay and puts it on the inexpensive standard relay.  Then the Volvo relay is only used as a low current switch to activate the standard relay.  

The new standard relay is triggered by pin 87 on the original fuel pump relay and receives its main battery power from pin 30 of the original relay circuit.  As an option, you may instead run a dedicated battery wire to pin 30 on the new relay. I suggest 12 gauge wire. This should provide a bit more voltage to your pumps.  If you do this, then the wire should always contain a fuse between the battery and relay.

Below diagram is for K-Jetronic Volvo 240.

Below diagram is for LH-Jetronic Volvo 240.

Adding a Tachometer to your Volvo 240 in place of the Clock

Adding a tach to my '83 240 DL way back in 1990 was the first 240 mod I ever did.  It's a very basic install, but can be a bit puzzling for a beginner. These instructions will also show you how the small clock is installed. 

Adding a Small 52 mm VDO/Volvo Tachometer to your 240

While less popular than adding a large tachometer, Volvo made a small 52 mm tachometer available for 240 owners. 
They are fairly rare these days.  Here are diagrams for wiring it up.  

Fixing the 240 Driver Door Lock Switch Wires
I have seen a fair share of emails like this one:
"I own a 1993 Volvo 240 Sedan. It has about 100,000 on it and runs beautifully. The only problem is that the central locking system seems to be malfunctioning. It makes a fast clicking sound when driving and sometimes goes up and down when one tries to unlock the other doors from the drivers side. In the past two days the battery died due to something being left on.  I pulled the #8 fuse (courtesy lights, clock, trunk light, glove box light, central lock system, power antenna, radio) and today the battery was fine."

This is an extremely common problem that affects ALL YEAR 240s equipped with CENTRAL DOOR LOCKING.
How do I know this problem is common in all year 240s? Because when I discovered this years ago i spent a day at junkyards pulling off door panels on a lot of 240s up to the 1993 model year. 
They were all the same.  Bad!
The problem is old, bad wires inside the driver door. Specifically, the wires going to the key lock switch ("F" in diagram at left) and also likely the door lock plunger switch ("A" in diagram at left).  It should be pretty obvious once you open the door up and look closely at these wires. The insulation on these wires will crumble and fall off, allowing the wires to short. This causes the rapid lock-unlock to occur. And when the car is parked, the shorted wires may allow the locks be stuck in UP or DOWN mode, which will kill your battery in a few hours.  The solution is to cover the bad wires with heat-shrink tubing, liquid electrical tape, etc., or cut them out and crimp or solder in new wires.  You will probably only have to do this to about 8 inches of wires, but  keep an eye out for more than that. 
Here are a couple good threads:

Dealing with the Temperature Compensation Board in your 1986-93 240
I won't go into great detail here, since there is already an excellent article on this subject linked below.  In a nutshell, Volvo got tired of people complaining about fluctuating needles on temp gauges. For the 1986 model they began installing a circuit board in the gauge cluster that changed the function of the temp gauge so that it would remain stable in the "normal" range at all times unless the engine was cold or very hot.  The gauge then had only a few set readings instead of a true variable reading.  The compensation boards generally work fine until they get old and cause mysterious high-low fluctuations for no reason. If you're trying to determine what your high-low fluctuations REALLY mean, you can buy an infrared (IR) temperature reader and check your top radiator hose temps for abnormal changes. To fix the problem, iPd offers a simple bypass wire you can buy for cheap here:  They also offer replacement compensation boards for more money.  Or you can follow the below instructions for your own DIY repair . . .

Here are the instructions for the iPd bypass:

And if your interested in a DIY repair, Peter A. submitted the following: 
The circuit is kind of clever. It can be repaired rather than just eliminating it.  It does require a soldering iron and a solder sucker to desolder the old parts. 
Pretty much the only things that will fail is the integrated circuit U1 or output transistor Q1, both of which can be purchased on-line from Digikey or similar places for about a dollar. U1 was bad on my board.  After 25 plus years it would also be wise to replace the electrolytic capacitor C1.
Click here for a PDF diagram and photo of these circuits: (270kb)

And Dirk W. submitted the following for those interested:
Lots of people will claim you need a new temperature compensation board (PCB), but that's not what's really wrong most of the time.  I have found that the metal pins that are mounted to the main cluster PCB are generally not properly soldered to the PCB.  They APPEAR to be soldered, but if you touch a soldering iron to the solder blobs that cover the heads of the pins, you will find that the solder is not wetted to the pin heads and these connections are almost always bad somewhere.  A little work with some sandpaper on the heads of the pins and resoldering the heads of the pins to the PCB will fix most temperature gauge issues.