We hit a bump in the road at speed just before pulling into a parking lot. I mention parking lot because frankly I did not notice if ABS light came on immediately or once we started car a few minutes later. Now ABS light stays on. I must have rattled something out of place..
The ovp fuses are good, but still I replaced it with a new one I had with me in the trunk - no change. Is there a fuse in the box, or elsewhere, that I should look into ?



1987 300SE- Euro

When you start the car does the ABS lamp go out?

When you start moving does the ABS lamp come on?

The answers will determine where to start diagnosis.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

oops, I guess I failed to make myself clear yet again..
ABS light comes on - with all the other dash lights - when I turn the key to start the car but stays on brightly all the time while car is running (the other lights go out immediately as they should. ABS Light goes out when I turn engine off - key all the way to the left.

thanks



1987 300SE- Euro

That is the answer to start a diagnosis.

IF the ABS lamp never goes out then, there is a voltage issue. Start at the overvoltage relay & then proceed to the ABS 6-pin relay on the hydraulic unit.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

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Well, if one reads that as written, it says you replaced the fuse...is that what you meant to say ??? ..or do you mean you replaced the OVP relay??

__________________
A Dalton

Hi

I first checked the fuses which were good.
Still I swapped the whole OVP unit with a new one I had in the trunk - I had read many threads here about how the OVP might still malfunction even though the fuses were good. This did not remedy the situation



1987 300SE Euro

I won the idiot of the day award. Woo hoo!!

I read the post too fast ma bad.

__________________
1986 300SDL, 211K,Dealership serviced its whole life
1991 190E 2.6(120k)
1983 300D(300k)
1977 300D(211k)

Why do you think Doc asked if the abs lamp was On before the car was moving ????
He has a power feed problem.

__________________
A Dalton

M.B.Doc - Which is the six pin relay you are referring to ? Is it inside the cover of the hydraulic unit ?- I do not see anything like an attached relay on the outside of the black plastic cover.

How about cases where the ABS light is out [following lamp test] for a short time, then comes on typically just at a moderate bump [expansion joint for example]. Before the light comes on you can induce ABS activation [say by hard braking, with the right side wheels on sand or leaves]

I recall seeing something about the connectors in the relay socket needing to be re-crimped. If this is the fix, what sort of tool is needed? ["Kablex" connector tools?]

OK. The battery is good and everything else electrical in the car that I can tell, works fine. I found the six pin relay inside the ABS hydraulic unit.It is held in place very snugly so I don't think re - crimping is an answer for this specific unit. Is there a procedure for checking the relay it that I could do myself ?

1987 300SE Euro

Check pin sockets 30 to ground and 15 to ground for power from OVP . Key ON

__________________
A Dalton

Hopefully the following readings can give an indication for what I should look for next. I checked the silver six pin relay inside the hydraulic unit like Arthur suggested -KOEO. Pin #30 to ground gives me 1.225 v and #87 to ground reads 12v. I could not see a pin #15,(different configuration?) but outside light was not great, so I need to look again in the morning.

the six pin relay is #0015426719. The ABS unit itself is the newer version from 1986 or 1987 - where the ABS lettering is stamped on the incline side of the plastic cover.
I did not find a socket #15 for this relay but still looking for a solution.


1987 300SE Euro

As the title indicates - I am still looking for assistance.

I went ahead and pulled the 2 front ABS sensors out and cleaned them. They were both plenty dirty , but that did nothing for eliminating the Yellow light from the instrument cluster. Any Ideas ?
I would like to pursue the electrical rather than the mechanical road. I too believe there lies the answer.


1987 126/300SE Euro