I was listening to my stereo today, with the front heater fan on, when I
flipped the switch to turn on the rear window defroster. As soon as I did
so, the stereo went dead -- no sound, all lights out. "OK," I thought, "this
is simple. They must all be on the same circuit and the additional load from
turning on the defroster blew a fuse." I then flipped the defroster switch
back to the "off" position and -- here's the odd part -- the stereo went on.
I tried this several times: defroster switch  "on," stereo off. Defroster
switch "off," stereo on. So I decided to leave the defroster off so that I
could listen to the stereo. By now, I had also turned the heater fan off.
When I tried to turn it on again -- guess what? -- the stereo went dead
(even though, just a few minutes earlier, when I had the defroster off, both
the heater fan and the stereo were working).

So, to sum up: the stereo works fine if both the defroster and the heater
fan are off. If either (or both) switches are set to the "on" position, the
stereo goes dead. This has me completely stumped. I have never had this
problem before. I'm hoping that someone with some knowledge of electrical
circuits can deduce what's causing this to occur and suggest how to fix it.

--
Ray Reinhard
'86 Westy