So I'm fighting with my power windows, and would really appreciate some assistance. My car with a Chevy 350 has been re-wired with a Painless wiring harness, and seems to be chewing through window switches. I am using 82-92 GM F-body (Firebird) window switches with no relays, as both the guy that re-wired the car and my trusted mechanic said I didn't need any, and that the switches should be able to handle the current draw just fine.

After an afternoon drive yesterday, I failed to notice that the passenger window switch was stuck in the up position. Not sure why. I returned a couple hours later to take the car for another drive, smelled burnt toast from within the car, heard the 30-amp metal fuse in the fuse box clicking every few seconds as it cycled on and off, and saw thin wisps of smoke rising from the window switch. All of the terminals were melted and the passenger switch wouldn't move. The drivers side switch moved (wasn't melted), but the window didn't work. I disconnected the battery and all was ok for the time being.

This morning, I replaced the 30-amp fuse in the block and the driver's side window went up/down fine. I cut off the connectors to the passenger switch and hooked up a spare window switch I had, but no go. Window wouldn't move. I wonder if the stuck switch fried the motor. I went ahead and ordered a used one.

I've read threads that stated the front windows DID, and did NOT have relays from the factory. Can anyone confirm which is correct for an '86 XJ-S? Also, do these window motors pull an unusually high amount of current that makes relays a necessity? The Firebird switches have thick 14GA wiring, and seem pretty heavy duty, and I'd heard the originals had spotty reliability. My Firebird switches have worked for months at a time just fine, but then one or the other seems to fail...about 3 so far. And these Firebird switches aren't cheap—$50 each (whereas I see that repro stock switches are available for $10 each on Ebay).

I hope to be installing my interior soon, but really want to make sure these miscellaneous wiring issues are resolved before everything is much harder to access because of being covered with carpet and consoles.

Thanks in advance for any assistance!

 

Original configuration was a single relay for both windows. For a coupe, at least. Not sure about the H&E cars, if that’s what you have

I suspect a faulty motor and/or jammed window mechanism is overloading the circuit.

As for Firebird switches: Look up a Firebird wiring diagram. We’re relays used in the circuit? I suspect ‘yes’, as that’s the norm.

Cheers
DD

 

Thanks Doug. I'm researching possibly retrofitting the "early HE-stye" black glossy window switches back (what was originally on my '86), and use a higher quality relay on BOTH. Just need to put my hands on a diagram that identifies each pin/wire color from the switches.