B-Body Chevy Window Issues

Anyone have experience with 90’s Chevy electric windows? My wife’s Caprice wagon has a dead driver’s window. So far I have verified that the motor and switches (common failure point) are good and checked that I have 12V and ground at the switches. I also pulled the wiring harness and ensured there were no broken wires between the door and body.

The manual I bought has all the chassis wiring except the doors so I am at a loss for what is causing the behavior I’m seeing. All the other windows work from either switch, but the window lockout selector no longer disables the other door switches. With the lockout in one position the driver’s window does nothing at all. With the lockout in the other position trying to put the driver’s window down draws a lot of current dimming the lights and heating up the wires.

It seems there is a short to ground through the window lockout wiring but I can’t figure out how that could happen or why the window doesn’t work in the first place. I have had the door apart several times and swapped several relays and circuit breakers chasing the issue. At this point I’m stuck on things to even try. Has anyone ever seen a failure like this or know the secrets of where the 20+ wires from the door are going?

A topic there isn’t a GRM expert on? Thinking on this further there must be more to this system that I am not seeing. Does anyone know of other relays or circuity, likely under the dash for the door controls?

Do you have another window lockout selector switch that you can try? (good luck finding one) It sounds like that particular switch has failed and is shorting to ground in one position and not functioning in the other. Seems like you have gone through everything else.

Luckily I have a parts Caprice so initial swapnostics were easily and cheaply performed. This gave me confidence in the switch and motor. Window works fine if jumpered from a 12V source to the terminals.

Well other that that I got nuthin. I Know H-body has a ground bus under the carpet at the drivers door that will corrode and cause all sorts of strange things to happen. Don't know if B-body has the same, chasing wiring shorts is the worst.. Good luck.