number #10 on the 50 item "to do list" on my beatup 90-5 speed;
Got the speedo and odo working yesterday. ( Thanks Art ) But there is an issue that I suspect you geniuses have seen, or can give me a suggestion as I am not good with wiring diagrams. The speedo works fine except that when I engage the turn signals, it drops to zero, then resumes to normal function when the blinkers are no longer engaged. How are they related?

I bet all the ground wires need to be cleaned.On 740-940s there are about 8-12 in the corners under the dash,,,try findin them *& makesure the connections are not corroded.

Have you read the FAQ?

I know that your car is not a 700/900, but many things are the same as your car.

Besides, I saw a 240 that had exactly the same instrument cluster that our '88 745 GLE had.

I would suspect a ground problem - because the indicators for your directionals draw more current, they may be requiring more ground current than the speedo.

This happened to me when putting on the high beams in my '90 744 TI caused it to stall! This is in the FAQ - a bad ground in the left front fender caused the stall.

I suspect that your work on your instruments caused a problem for the instrument cluster ground.

I have no actual experience with your car, but electrical troubleshooting is one of my fortes.

Finally got around to working on this.
YOU WERE CORRECT. There are two grounds on the steering wheel that you could rotate with fingers. Removed, cleaned, reinstalled. Dimmer function and speedo are working perfectly now. Though emergency flashers stopped working.
Thanks!

Finally got around to working on this.
YOU WERE CORRECT. There are two grounds on the steering wheel that you could rotate with fingers. Removed, cleaned, reinstalled. Dimmer function and speedo are working perfectly now. Though emergency flashers stopped working.
Thanks!

OK boys! Did not consider that, but on a car of this age, there must be many corroded grounds. I will start removing, cleaning and re-installing.
Thanks