Expert: John Kingery - 1/23/2008

Question
When the wipers are on continuous, and the lights are on, changing the electrical load causes the wipers to halt for a few seconds, then continue. Changing the load includes brake lights, indicators etc. I have connected a separate ground to the wiper ground (brown wire) near the motor, as a test. This made no difference, so the fault is somewhere else, not in the ground. Where should I look next? Is there a common fault in the fuse/relay box?

Answer
yikes.

I had problems with mine on a '92 325i, and replaced the motor and mechanisms with a junkyard model before finding it was the wipre module. SOunds like yours MAY be the same.

On early 325's, it was under the drivers footrest (really DUMB place for anything electrical!).  On '94 and later, it was moved to behind the glovebox.  Likely yours is there too.  A dirty relay there could cause the problems you're describing.