I have a 1990 BMW 535i, the error F/Foglight is always on, and the foglights don't function. I occasionally get a License light error as well, but the bulbs etc... are new so it should work fine.

I've taken the Foglights apart and the bulbs appear fine, I've tested the wiring with a volt meter and although there is a some signal there, it is quite weak. The plugs themselves look as though they need to be replaced, and I tried cleaning the contacts as they appeared to have some corrosion or oxidation build up.

But now I understand that the LKM may in fact be the issue. That the soldering on the circuit board has a tendency to go bad, and needs to be redone. Before I go out a completely replace the LKM, I would like to try and repair it, but I've looked at the pictures on the E34 website that describes how to repair it, and I can't deduce what I am supposed to do.

If anyone has experience in this area, suggestions on how to go about fixing the issue, and/or narrowing the field of potential problems, I'd greatly appreciate any assistance you might be able to offer me.

Thanks
B.