SPEDO & CRUISE NOT WORKING
 

I Have A 1990 300e 2.6 , With The Cruise & Spedo Not Working Any Ideas On Where To Start? :

If the speedometer is out, the cruise control won't engage, so I'd start with diagnosing the mechanical speedometer. Perhaps you have a broken drive cable or it could be the VDO unit itself.

I had the same problem on my W123, and it turned out that the cable had come loose and simply backed out of the speedometer head. I had to fabricate a pair of those instrument panel puller thingies from a coat hanger, but it was an easy fix. My philosophy is to check the simple things first; good luck.

Best Regards,
Rob