Power Window Relay Mod on Rear Window

[1987 GMC Jimmy]

When my motor was worn out, I just used a drill to do turn the drive cable. I also used silicone lube in the tracks and runs, and your new motor will love you for that. I’ve still got a problem with mine, and I think it’s the stupid 100 year old switch. I knew how to jump the motor this summer after some trial and error, but I can’t remember it now. I’d apply power, and the motor would turn, but under load, it didn’t do anything. Sorry that’s not much help on my part, but it sounds like you’ve gotten a handle on it.

 

[rpcraft]

When my motor was worn out, I just used a drill to do turn the drive cable. I also used silicone lube in the tracks and runs, and your new motor will love you for that. I’ve still got a problem with mine, and I think it’s the stupid 100 year old switch. I knew how to jump the motor this summer after some trial and error, but I can’t remember it now. I’d apply power, and the motor would turn, but under load, it didn’t do anything. Sorry that’s not much help on my part, but it sounds like you’ve gotten a handle on it.

Yeah, I already had been using the drill, just because I am waiting to get my move until I put the new harness in, simply because I know at some point I need to be able to have the windows rolled up until I can get moved in and get the garage organized. Fro the move I have a bunch of crap in the back of it that is in the way now so that won't be an option come move day. I went and got a new motor, and was able to get it up but man it was weak as heck and I had to operate the power probe with one hand and push upwards on the window with the other. The PO had some crappy tint on it that is coming on done, probably providing a lot of resistance in the track, and also all the felts and parts that operate it need to be rebuilt and regreased. I figure also maybe the amperage allowed by the power probe might not be the same as having a good 10 or 12 gauge wire running to it,

 

[rpcraft]

I got out in the shop yesterday and was able to run a proper 10 gauge jumper to the harness and it made a huge difference. I still need to take the assembly apart and rebuild and clean it, but the power probe is definitely not able to transmit the current in the same manner as a proper gauge wire. Messing around with it inspired me to go ahead and finish pulling out the rest of the main harness.... What a mess that was. Mystery black alarm box with multiple fuse taps and splies with momentary press switches.... I'm guessing it is a good thing I went ahead and picked up a aftermarket harness but I am still going to have a few things to figure out. Oh well, at least for now i can use my 10 foot jumper cable to roll up the windows, lol.

 

[Burbdually73]

A thought came to me while looking at the relay mod for the power windows in our square trucks. Could that same mod be applied to a power rear motor? It has an up, down, and off position on the switch just like the side power windows. You could pull 12V right off the junction block and splice the relays in right where the wiring exits into the engine compartment. If you use weather pack connectors the system can be used with or without relays in case you're in the middle of nowhere with a relay that went bad you can just unhook the relays and connect the system back to factory.

@Milblazer did you use a constant hot or an ignition hot?