79’ K5 back window electrical problem

[Gnarlor]

Hello everyone. I’m new to K5’s and CK5. This site has been the most helpful resource I’ve found for my 79’ Blazer. Thank y’all

I have plans to customize the Blazer but I’m stuck on figuring out a short in the wiring of the back window. When I bought the Blazer it worked but it stopped all of a sudden. I’ve been chasing down the short but I can’t find it. The switch in the cab allows a closed circuit but there is no power coming into it. I checked the wires where they plug into the firewall on both the cab and engine compartment sides and no current.

From there, as far as I can tell, the wires run to the tailgate. Where do the wires get power? Do they run back to the battery from the tailgate? I’m stumped. (I suck at electrical stuff anyway)

I’ve included pictures of what I’ve done so far. Any help is appreciated.

 

[frankin5]

The rear window has two power sources that come from the fuse block and both have 30 amp fuses. I fuses are good, problem in wiring, if no power to fuse block, then it is a fusible link problem. This is 1991 diagram, earlier may be different.

 

[Gnarlor]

The rear window has two power sources that come from the fuse block and both have 30 amp fuses. I fuses are good, problem in wiring, if no power to fuse block, then it is a fusible link problem. This is 1991 diagram, earlier may be different.

Thanks. I’ll check the fuse block. I checked the fuses but I didn’t check for power

 

[Gnarlor]

The rear window has two power sources that come from the fuse block and both have 30 amp fuses. I fuses are good, problem in wiring, if no power to fuse block, then it is a fusible link problem. This is 1991 diagram, earlier may be different.

I checked the fuses. A few were the wrong amperage and I changed them. There is a 30 amp fuse where a circuit breaker is supposed to be. Would that cause a problem? Where are the fusible links?

 

[frankin5]

What did the cut off RED wire go to. The fuse will just blow as a circuit breaker will reset. Did you find both hot wires at the fuse panel for the rear window. Fusible links are a form of slow blow fuse. They are found in circuits that are tied to the battery.

 

[Gnarlor]

I don’t know where the RED wire is supposed to go but it’s hot. I’ll pull the panel and look for the wires to the rear window. The wiring is a rats nest. Thanks for giving me some guidance

 

[JoshHefnerX]

That wiring back to the tailgate is undersized. You may have burnt the insulation on it at some point. Also, the motor grounds out via the casing. Make sure the casing/tailgate has a good ground signal. It's kind of a monkey shit setup to begin with.. :-(

 

[rampage]

^^^
Yep, use a dedicated heavy gauge wire and ground the motor case directly to the frame. But I have a feeling that’s not your problem.