Electrical Gremlins - Window Circuit

[T.P.Crockmier]

Hello All, I have an '86 300 SDL that is having some electrical problems. It started when the drivers window switch broke, so I replaced it with the HAP branded switches from the Pelican Parts Catalog. I also replaced the rear passenger switch which is on the same circuit. Here's a rundown of what's happened since I replaced the switches.

• I replaced the rear passenger switch first. It sent power to the motor but there is something else preventing the window from going down.
• I replaced the drivers switch next. The window went down 1/2" and then the fuse blew.
• The motor is fine. I connected it straight to the battery with the assistance of a friend and verified that it works well.
• The new drivers switch was verified as good by connecting it to the passenger window circuit. It operated the window just fine.
• The connectors for the switches in the console have been verified as not having a short within them.
• The fuse would blow ever time the drivers switch was depressed. I never checked if it would do that when the rear passenger switch was depressed.
• I did my best to verify the integrity of the wiring running through the door hinge. Everything looks good in there.

Then, after I purchased more fuses (25A) and verified that the fuse box contacts are not corroded, the problem changed. Now, the fuse blows when the key is turned to the accessory position. Every time, without fail. There is this W126 power window question thread from not too long ago where someone had some power window issues and the community pointed to relays, but since my other window fuse is totally fine....I don't know. I'm over here scratching my head.

I'm reaching out to the community for any advice, tips, tricks. Hopefully someone has dealt with a similar issue. Any responses are greatly appreciated. Thanks in advance.

[Alec300SD]

PS rear window not opening - probably bent window regulator or binding of the glass in the window channel.

Blowing of fuse when in accessory key position - probably short circuit in DS electric window wiring harness.
The wires fray after years of opening and closing the DS door.

[T.P.Crockmier]

Originally Posted by Alec300SD

Blowing of fuse when in accessory key position - probably short circuit in DS electric window wiring harness.
The wires fray after years of opening and closing the DS door.

My understanding of the system is that the harness going through the door is dead until the window switch is depressed. When the fuse was blowing only when the switch was depressed, the harness through the door hinge was the first thing I was told to check. It is extremely hard to access that particular area, I did my best and to my best knowledge, the harness that goes through the door hinge is okay. With the fuse now blowing when the key is in the ACC position, it seems more likely that the live wire to the console switch has a short somewhere.

Thoughts?

[jay_bob]

The window switches are arranged so that the wires going to the door are hot all the time.

This is so the back window switch can work.

See here: cleaning the window switch restored rear window

[jbach36]

I was told that the aluminum fuses pit after time and even though they might LOOK good, they might not BE good. So they (?) increase resistance on other electrical things and cause problems. Change out all your fuses, they're very cheap. You can probably get a whole set for $15.

As far as the stuff on the inside of the door, the plastic guide rails might be toast, preventing the window from moving. Check to ensure all could work well, if the electric was working fine. Lube whatever needs to be lubed. Get rid of the old grease that has turned into peanut butter consistency over the years.