I turn on the A/C, I get a F/FOG LIGHT + LOW BEAM

[rps1072]

On my 1994 525iT
Almost every time I turn on the A/C, I get a F/FOG LIGHT + LOW BEAM warning on the CCM.

While this is happening:
The left turn indicator on the instrument cluster is partially illuminated
The dashboard does not click when the turn signal is on
The left high beam headlight is partially illuminated (even when headlights are off) and switches off and on, alternating with the left turn signal

These problems go away when the A/C is off.

Things I have done to remedy (basically everything that I have found in posts and that is common sense):
New LKM
Cleaned and checked all connections
Changed bulbs
New voltage regulator for alternator

Could it be the alternator itself?

[winfred]

what you have is a bad ground the fun part is finding it, the reason why you have lights coming on is they are the nearest path to ground for the effected circuit

[rps1072]

Can you help me narrow it down to a certain area?

[winfred]

without getting my hands on the car id guess it's a under hood problem, look for grounding points on the body and see if they are loose nut/cruddy/broken lug, you'd be amazed the weird stuff that can get affected by a bad ground that shouldn't be connected

[632 Regal]

Check the grounds at the compresser first! sounds like its backfeeding through the dash cause of a bad ground...not really a good thing at all!

If that dont help...

Go from the battery forward, unhook/clean/replace. then like Winfred says go under the hood, bumper, everywhere you can find ANY wire hooked to the body,bumper,frame and clean.

[winfred]

if the comp is not grounded it don't run, the clutch grounds to the compressor and that gets it's ground through the bracket to the block, possible the main engine ground may be weak, you can check for that with a pair of jumper cables, hook the engine to the body, i like to use my multimeter on 10A setting and connect the motor to the body while it's running, anything over 1/8-1/4 amp and somethings wrong, usually engine ground problems show up in running problems and temp gauge readings


Check the grounds at the compresser first! sounds like its backfeeding through the dash cause of a bad ground...not really a good thing at all!.

[rps1072]

Thanks very much guys. I checked the big wad of brown ground wires grounded to the left side of the engine compartment. The nut holding it on was somewhere between loose and falling off. I tightened it and cleaned the contact. Funny thing: not only do the lights work correctly, but everything else works a little better and the car runs better. I am going to be really irritated if that is all that it was. Grateful, but irritated.

Thanks again.

If only the speedometer worked, all would be right with the world.