ABS Light Always ON
 

This pertains to a 1983 500SL Euro (don't shoot me) that was never "Federalized", so there could be some differences between this car and the normal North American models.

Finally tossed a master cylinder in the SL and dragged it out of storage. As part of the TLC fest, I pulled the instrument cluster and painted the pointers on the various gauges.

Long story short, the bulb holder for the ABS light was empty. I got a new bulb and put it in and now when I start the car it comes on with the rest of the idiot lights prior to start, but then never goes off. I assume this is why the bulb was missing. I can confirm that the ABS does NOT work, can easily lock up the brakes and has been that way since we got the car back in the 90s.

I'd really like to get this taken care of. The car is scary enough as it is (seriously too much power for the chassis), and locking up the brakes causes my pants distress. I just don't know where to start with this. All the fuses are good and the OVP relay is working fine. Everything else in the car is working like it should, with the exception of the ABS and the A/C.

Where to start looking? I'd be ahead already, but can't seem to find my copy of the FSM for this car, annoyingly :mad:

Could that bulb be for some other item thats at fault ..Swaping out the speedo by other owners, this will some times be the problem ,,as the bulb holders get put back into the wrong hole.

Don't assume the OVP is operating correctly. How did you test it?

The bulb is in the correct location. Still has the factory wire numbers on it.

The OVP relay is working, otherwise the idle runs high. Went through that a few years ago and installed a new replacement at that time. The idle control is working perfectly. Starts with a fast idle, then drops as the engine heats up. Once it's warmed up, the idle doesn't change.

Since the bulb was pulled, I'm assuming it was because it was "on" and the PO didn't like looking at it anymore.

The ABS light on my 1983 280 SL is always on too.
I put black tape over the light.
I never ever felt the ABS pulsing on hard stops so I guess my ABS is not working either. But I can stop on a dime with that car.


jz

You can test the ABS wheel sensors with a meter. I have a sensor that is intermittent. When it fails, the light comes on. Can't remember what the proper ohm range is but probably available here somewhere.

I think I've found the problem. The wires going to the rear sensor in the differential are broken off. When I get a chance to get under the car and look closer, I'll report back with what I find. I'd suspect that would certainly set an ABS fault!