1981 300SD--intermittant rev counter---- coming and going when car is in motion drops down to zero---SYD

Are you referring to the tachometer? If so the diagnostic plug could be faulty.

------------------
Benzmac:
ASE CERTIFIED MASTER AUTO TECHNICIAN
LEAD TECHNICIAN FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

Re Rev counter/tachometer thank you for advice cleaned plug put a small shim behind it and it was perfect---syd

My 81 300SD tachometer has never worked since the day I bought it, but it hasn't worried me too much, plus I'm really lazy and since my car still runs fine, I figure that the car just doesn't want me to know how fast the engine is turning. Sorry, I know that's no help for you, though. Happy motoring!!

Where is the diagnostic plug??

raise hood it is located driver side and mounted on the fender(wing)--- I unscrewed plug and removed unit--- then with a hard pull it pulls out the base ---cleaned pins placed a small shim in the top and put plug together and rescrewed it in the diagnostic ---worked perfect----Tex Bill\while it wont make your car run any better and is it really needed on an automatic---as it is there it might as well work ---this was why I was looking to do it myself---thanks for all the help and interest----I have other questions to ask and I'm sure the response will be as good

you're right SYDDONNA if it's there it might as well work. I said that about my A/C all last summer but I suffered anyway because I couldn't afford the Robert Dinero to get it fixed. I do as much as I can myself, and someday I'll get around to the tach, maybe when I'm ready to part with the car. Best Wishes,

------------------
TXBill
82 300 SD
79 240 D