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How to repair the 740 odo- & tripmeter

A very common problem for the Volvo 740 (and also 760, 780 and 900-series) is the tripmeter and odometer (or: mileage indicator) which stops working. If the speedometer is still working the problem is in most cases very simple: inside the instruments unit there is a very small cogwheel which is made of nylon. Sooner or later a small tooth (or even several teeth) will break and the tripmeter will stop working, resulting the odometer to stop working. But with this step-by-step tutorial it’s very easy to fix this problem!

How to get the right cogwheel for your Volvo 740

Volvo used two brands for their analog milometer/speedometer-instrument: VDO and Yazaki. It isn’t hard to recognise it: the VDO doesn’t have the “splitted numbers” at its tripmeter. The numbers of the Yazaki are seperated as you can see on the picture below.

Volvo 740 940 700 900 Yazaki VDO speedometer milometer recognition
How to recognise a VDO or Yazaki speedometer in your Volvo 700 or 900-series car (click on the image for a larger version) 

Now you’ll know if you have a Yazaki or VDO-unit in your car, but the cogwheels can vary due the number of teeth on the cogwheel. When you remove the speedometer instrument of the instruments unit a number is visible (also some numbers on the back) which help to order the right cogwheel for your car. If you insert the wrong cogwheel the unit will give incorrect values of the distances so the tripmeter will turn too fast or slow and the mileage will be wrong. The removal of the instrument is described below.

Requirements for the cogwheel-replacement:

  • a new cogwheel (sold at Erich Technical Support, IPD, your local Volvo-dealer and other webshops)
  • a small flat screwdriver
  • a Philips screwdriver
  • not neccessary: a knife or nipper to cut the tie-wraps of the cable harnesses which are connected to the instrument cluster
  • not neccessary: glue to fix the needle of the speedometer if it’s get damaged at the removal.

How to repair your odometer and tripmeter of your Volvo 740 or 760/780

With this guide you can easily repair your broken tripmeter and odo/milometer. Just follow the steps below and it’s a piece of cake!

This tutorial is written for the Volvo 700-series until 1991 (since MY91 the dashboard is changed to the version of the 760/940-series), a how-to for taking the dashboard of these late types will appear soon.

If you want to be sure not damaging any electrical components please disconnect the negative battery cable.

Click on the pictures for a larger version (will open in a new tab/window).

Volvo 740 GLE 1990 dashboard instruments gauges
The dashboard of a Volvo 740. In this case a MY90 Volvo 740 GLE.

Step 1: remove the small covers with a flat screwdriver (or knife)

Volvo 740 odometer remove how-to tutorial
Removing the cover on the left side 

Volvo 740 speedometer instrument gauge unit removal
Remove the small covers on both sides to expose the screws that holds the instruments unit into the dashboard

Step 2: unscrew the Philips screws

Volvo 740 760 instrument cluster removal Philips screws
Remove the screws on both sides with a Philips screwdriver 

Step 3: removing the instrument cluster

Please note: put the turn signal and wiper stalks down to remove the instrument cluster. Now you can pull the instrument cluster away from the dashboard.

Volvo 740 760 instrument cluster removal
After removing the screws and turn down the indicator- and wiper switches you can remove the instrument panel

Step 4: remove the connectors at the back of the instruments unit

Remove the connectors at the back of the unit. Please keep in mind which cable is connected on which place. If the cable harnesses won’t come out a lot you can cut the tie-rips between the cable harnesses to provide more space and remove the unit easier. In most cases there is a plastic clip which operates as a seal at the speedometer connector. You’ll need to remove it before the connector can be peeled off.

Volvo 740 760 instrument cluster back cables connectors
Cables and connectors of the Volvo 740 instruments cluster

Volvo 740 dismantling instrument cluster panel removal
Almost there!

Volvo 740 760 instruments cable harness unit removed
Done! Please keep in mind which connector is connected where on the back of the instruments unit (but it will only fit in one way) 

Step 5:  dismantling the instruments unit

It’s time for the hard work now: taking apart the instrument cluster. But I’ve made an image with which screws should be taken out to open the unit.

Volvo 740 760 instrument cluster unit
The Volvo 740 instruments unit

Volvo 740 760 780 instrument cluster back lamps lights connectors
The back of the instruments unit 

Volvo 740 instrument cluster back lamps lights connectors highlighted
The screws you’ll need to remove are indicated with a red circle

After you removed all the screws remove the clock adjuster. Now you can remove the white backpart of the unit away from the black front. Please be carefull and don’t damage the instruments and pins.

Volvo 740 760 odometer gauge instrument panel disassembling
The unit taken apart

Take out the speedometer gauge very carefull.

Note: nouw you can see a number in the low right corner of the dial. That number will help you ordering the right Volvo cogwheel for the odometer and tripmeter. There are also a couple of numbers on the back of the gauge which might be needed for ordering the cogwheel.

Step 6: disassembling the speedometer gauge

Now it’s time to disassemble the speedometer instrument, so we can get to the odometer gear.

Volvo 740 940 760 960 VDO speedometer odometer mileage indicator tripmeter
The speedometer unit

Removing the speeding needle is pretty difficult. If you use two screwdrivers you can pull away the needle but please put some fabric or small cardboard-pieces to prevent damage on the dial cover. Some people prefer to take out the round center of the needle, but in that case you’ll need to glue the center back when putting the speedometer back together.

Volvo 740 940 760 speedometer dial needle removal
The needle is now removed

Now pull away the dial sticker and three screws will appear.

Volvo 740 speedometer tripmeter UAF2115 gauges odometer
The back of the VDO speedometer gauge

Volvo 740 760 dial sticker speedometer electronic VDO sticker removal
The dial sticker is removed

To seperate the mechanical part and housing you’ll need to remove the 3 small screws. Use a flat screwdriver to remove them.

Volvo 740 speedometer housing cogwheel gauge mileage odometer indicators tripmeter VDO
The meters and housing are now seperated

Step 7: replacing the cogwheel

Volvo 740 760 940 960 odometer mileage indicator tripmeter mechanical parts
The odometer and tripmeter are now naked, but the odometer gear is still hidden 

The cogwheel is located on the right side of the unit. As you can see on the picture above and below there is a PCB with several electronic components on the right side. Below these parts the cogwheel can be found. You’ll need to remove two screws (see below) to remove these components. Please be carefull: the electronic wires may not be damaged or removed!

Volvo 740 940 meter driver pulse UAF2115
Remove the 2 screws and the cogwheel will be exposed

Volvo 740 760 sprocket cog gear wheel tripmeter broken tooth teeth
A very common problem for the Volvo 740, 760 and 940: a broken cogwheel. When one or more teeth are broken (you can see the broken tooth below the cogwheel) the tripmeter and odometer stop working

Now remove the broken cogwheel and replace it with the new one.

Volvo 740 760 940 broken gear wheel sprocket tooth teeth replacement cogwheel
The broken and new cogwheel

Volvo 740 sprocket gear wheel tripmeter mileage indicator instrument replaced
The new sprocket in its socket! And the big wheel seems a bit surprised but hey: it works!

Step 8: reinstall all parts and put it back together!

To finish the repair please do all steps above backwards (except installing the broken cogwheel of course) and enjoy a working trip- and odometer! And don’t forget to set the right time on the clock.

If you wish you can also replace some lights. It’s pretty easy and a cheap fix. The right lamps can be bought at your local car parts store, the Volvo-dealer or any webshop.

 

Other common problems of the Volvo 700 speedometer

If your odometer and tripmeter doesn’t work but your speedometer does work fine the problem is in almost every case a broken cogwheel. Sometimes the little electronic driver which is above the cogwheel is broken but it’s pretty rare.

If your speedometer also doesn’t work the problem can be found at the rear axle and driveshaft: a sensor is installed to calculate rotations which delivers the right speed and distance for the speedometer and odometer. But sometimes the cable and connector at this sensor is broken. You can clean it (solves the problem in most cases), repair it or replace the connector and/or cable (also very common) but sometimes the problem can be caused on the gauges unit itself: corrossion or a bad solder can damage contacts and capacitors or other components like the UAF2115 chip. A visual inspection will find the cause in most cases.

If you have any questions, please feel free to e-mail me on info@volvotips.com!

© Volvotips 2012

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