Use of fog lights or defrost cause ABS warning light

[Leo O'Farrell]

I just bought an early 1995 coupe. Driving it back to the SF Bay Area from Atlanta GA, I noticed the ! light and ABS light would come on when using the fog or defrost.

The warning light would reset after the next engine shutdown, strartup.

Is this a known fault, or where should I start looking?

[kang]

Strange as it seems, you might have an alternator or battery issue.

I think I recall hearing that the ABS system will shut down if the battery voltage is low, or if it detects that the battery is not being charged enough, or something along those lines. The ABS light illuminates to inform you of this. Fog lights and the defroster (you mean the rear window defroster?) both use a lot of current, so this would exacerbate the condition.

Do you have ABD? It shuts down when ABS shuts down (they use some of the same systems). If you have it, and the ABD fault light is not coming on when the ABS light comes on, then perhaps something else is happening. If you don’t have ABD, then nevermind…

[Leo O'Farrell]

Thanks, I'll try charging the battery. I drove across country, so one would think it's charged, but it could be near the end of it's life cycle. I think a meter would show if it's got 14 volts or not. I'll check this.

Regarding ABD, I'm not familiar with this term. What does it stand for?

[AFJuvat]

Your battery and\or alternator is failing.

ABS is the first thing that "powers down" due to voltage issues

[Leo O'Farrell]

It did it again today, but on closer look, it's ABD not ABS that goes off. The automatic brake differential, an option this six-speed car has for better traction when starting out on loose surfaces.

Does that affect your diagonisis at all?

Thanks.

Leo

[kang]

Have your battery & alternator checked by a competent shop.

[bigchillcar]

should he get a check with the bosch hammer? sounds like an odd problem. i'd be curious what codes pop up.