Hello

I have an 85 SD with ABS and the light has just come on. I have checked all the fuses and everything looks good, and the unit 'looks' fine; no holes in any lines or unplugged ends. Does anyone have any ideas what could cause this?

The car has about 150k and runs like a top, but the light just came on out of no where. There are zero vaccuum issues that I know of at this time, all the locks work perfectly and so do the vents.

Thanks

your engine running funny? Tach dead?

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hum.....
1987 300TD 311,000M Stolen. Presumed destroyed

Actually the tach did die right after the light came on, but the engine runs like a champ.

Check your OVP anyways. It might have gone out.

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hum.....
1987 300TD 311,000M Stolen. Presumed destroyed

Ah ok great, I will check it tomorrow and replace if needed.

Thanks a ton.

It may be just the fuse at the top, so check before replacing the whole thing

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hum.....
1987 300TD 311,000M Stolen. Presumed destroyed

This was one job I didn't do myself. Call me chicken, but I lost my nerve when it came to computerized braking.

My "wrench" told me it was a sensor. He used a cannibalized part from a derelict. Works fine. Sensor, that what it is, most likely.

Joe Marroso

bump

I ordered a new relay from Fastlane and installed it but the problems still persist. My tach and ABS light are still dead, any other causes? The fuse on the old OVP was good and it's not blowing the new fuse, but this didn't solve the problem.

It would be a pretty strange coincidence for the tach and ABS problem to be caused by seperate issues, but stranger things have happened.

Have you cleaned your wheels where the ABS wheel speed sensor rests? Also the rear diff.

See my old thread too:

http://www.peachparts.com/shopforum/showthread.php?t=283865

I would wait till your relay gets installed before you worry too much as that is usually the culprit for this problem. It should also be affecting your AC compressor too....is it still engaging?

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----Adam

1985 300SD 322,000

Check that you have a 12V supply into the OVP, --should have 12V on the Fuse....

Turn on Ign, then check that you have supply Out from the OVP....

10-1 there's no supply either to the OVP or its not being 'switched on' by the Ign circuit....

Check there's a 12V supply at the thick red leads in the ABS unit in engine-compartment under plug cover....

Any supply failures to ABS will cause it to lock-out into fault mode...

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http://i190.photobucket.com/albums/z...0TDnoplate.jpg

Alastair AKA H.C.II South Wales, U.K. based member

W123, 1985 300TD Wagon, 256K,
-Most recent M.B. purchase, Cost-a-plenty, Gulps BioDiesel extravagantly, and I love it like an old dog.

W114, 1975 280E Custard Yellow,
-Great above decks needs chassis welding--Really will do it this year....

Ok thanks guys, I will check into that in a couple of days when I have some more time.

I had the same problem. After about 10 min. of driving the ABS dash light would come on. The 3 wheel sensors ohmed out OK. Problem turned out to be the OVP Relay contacts were worn. Replaced it All OK now.
This relay on my 1991 350SD is located on the drivers side firewall with a clear red top that opens up for 2 fuses.
This relay controls the ABS & Idle & in my car it is next to the ASD Anti-Slip Relay Module.
Good luck
sidoog