we're swapping batteries and accidentally switched terminals on my 1990 300E.I saw a little smoke comingnear the alternator. The car startedright up and all instrument cluster lights went off except for theABS light stayed on. I first checked the fuse box, all wereok. Ihad autozone checked it out with their analyzer and found that it was not charging.They felt it could be a wiring shorted orit could be the alternator which is just a month old. Can anyone out there help me isolate the problem?Why is my ABS light ON?? is it connected?? I thank in advance.

 

Hi,
Likely you have fried the voltage regulator in the alternator. However there is a conflict between your statements. The alternator is not charging and all dash lights except ABS are off? The battery warning light should be ON. Does it come on when you first turn the ignition on (bulb check?)

You need to normalise the steering angle sensor.
Turn steering wheel (with engine running) from full left lock to full right lock and back again. The sensor has to know where the limits of travel are in order to work out straight ahead.
It looses its memory when the battery is disconnected. This is also the case with window lifts etc.

Good luck.

Stuart.

 

I had a similar problem with my 90 300E, my battery died and when I went to jump start it I put the jumper cables on backwards. I realized right away and swapped them.
Then the car started up, no problem. The alternator is fine since I can measure 12v with car off and between 13.8 and 14v with car on.
But the ABS light won't shut off. The ABS light was off and ABS was working fine before this happened.
Is there a fuse I might have blown? All the fuses under the hood look to be OK?
Did you fix your problem with your ABS light? Can anyone out there help me with this issue please.
Thanks, Tony

 

Guys I fixed it, there is a ABS relay behind the battery which had a fuse on top. I replaced the fuse and back to normal. Hope this can help someone else.

 

that is an overvoltage protection relay behind the battery.