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1991 240 Bad Speedometer

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  • 1991 240 Bad Speedometer


    I recently bought my son his first car... a 1991 240 sedan that has a bad speedometer. After doing a bit of research, we found that these speedos in the 91s can have bad capacitors or other circuit board issues. What we haven't found is any information on exactly which capacitors are known to go bad?

    Does anyone here know about this speedometer issue and which electrical part(s) is the culprit?

    FYI: We did inspect and clean the sensor on the differential and it appears to be fine. The car has only 107,000 miles and everything under the car (including the under-coating) still looks pretty new, so we're suspecting it's a circuit board issue.

    Any advice would be much appreciated!

  • #2
    I don't have a specific fix for your car, but worn out capacitors on PCBs from 80s and 90s era electronics are a common problem also in the retro computing world. I wonder if the same phenomenon is starting to plague us here in the retro car world. I would probably pull the gauge cluster out and inspect for capacitors that look like they have expanded and / or are leaking their internals onto the circuit board. In theory, you should be able to remove any suspect capacitors and re-solder on equivalent new ones. I have a intermittent speedometer problem on my 1991 240 sedan, I suspect it to be a problem related to age and sun baking the dashboard.

    Sorry no magic bullet, but just some thoughts.