I recently purchased a used 1989 E32 730ia and now winter is really coming in in Sweden and the defroster/rear window heat doesn't work I must ask help for this as there is no one anywhere near where I live that seems to know anything about these automobiles. I've called BMW in Uppsala but they can't analyze the car over the phone. When I press the button for defrost it lights up and the symbol for rear window heat also lights up but the window heat doesn't come on. I thought that those little wires might be broken somewhere so I had an entirely new back window put in. Still won't work. BMW pointed out that there is an electrical box under rear seat with many relays. All säkringar (fuses) are in place and okay. I replaced the relay that was responsible for window defrost/heat. Nothing happens when I press the button for defrost. The fan/heat works fine for front window but the back window doesn't get warm. I am NOT getting any power to the window wires but jesus what a tangle of wires is connected to this box under the back seat
Can someone please give me a tip/suggestion on what/where to check next that isn't too complex ? What a site this is..never knew it existed.