2016 Express 3500 Enterprise Rent a car special.
This truck had a problem a few years ago that turned out to be a bad fuse box in the engine compartment. About $700 later (just out of warranty by like 100 miles) it's fine.
Fast forward to this last weekend. Drivers window is working fine all day long. Last stop to pick up groceries. Window won't go up. Looking at the engine box, no dice. Find the under seat box. It's a circuit breaker it says. No way to reset it, it seems. Figure I'll take it home. Better than the hot parking lot. As I drive out I test it again - windows work again. So I rolled it up. On the way out it won't work at all again. Passenger window is also dead.

I'm not sure how to debug this one. Rip the drivers seat out, pull up the box and start checking? Maybe there's an easier way? Love to hear some thoughts.
Thanks

 

The circuit breaker is just a resetable fuse right?
It is over-heating from too high of a current draw. It trips. You lose your windows.

There is a GM Recall for my 2014 factory 'drivers window switch' because it may cause a fire if it gets wet under the right conditions. I am not worried. I think mine are from a different year now anyways. The first I thing I would do is change your circuit breaker. It is under your drivers seat, it looks like a big tin fuse. Just pull it out and put another one in.

After that, determine what is causing the current draw. Is the window mechanism too tight? It is greased? Is there something infringing the moment movement of the mechanism? A bad motor? Is there is a shorted wire? Bad electrical connections? Are the electrical connectors wet, or is there some fluid causing them to partially short out? Are they corroded?

 

Thanks. I didn't know if that CB pulled out or not. Pulled right out. It's conducting outside of the vehicle. I can move the ignition to start with the window switch down and nothing. No indication any juice is getting to it. Looks like I need to take the driver's door apart and look? Maybe it's the driver's switch on the door.

 

Passenger window checked on it's own switch or the driver's switch?

Possible the switch is bad or one of the wires to it has an issue.

 

Passenger's switch doesn't work either.
I ordered a new switch. Pulled apart the plastic and installed it. Way easier than I had thought it would be. Wires look like new. It's still not working. Either side.

 

Pretty basic stuff. Read the schematic.

https://www.gmupfitter.com/files/med...2016_en_US.pdf

 

Finally had time to look at it. Pulled out the front seat so I can see the fuse box. Started to troubleshoot. Seems that the relay is bad. The one right next to the circuitbreaker. I swapped it with the one next to it and window works again! Omron 13502749. Made in China. Seems the auto parts stores don't carry it. I can't believe one went bad so soon. 5 year old truck.

 

I would have said right off the passenger switch also not working is an indicator the problem is elsewhere.
Those four pin relays are pretty easy to come by, I don't think there's much difference in them. Rock Auto shows one that will replace several other 13502xxx numbers for as little as under two bucks.

Of course what I would do is just go to a you pull yard and pick up half a dozen and toss the spares in the ... well if you have a glove box or map pocket.