Power Rear Slider not working

Canadian GM Guy · November 3, 2019

So I'm not sure when it failed but today I wanted to open the sliding rear window, I pushed the button to open the window and nothing... No click from the relay no movement no nothin. I checked the fuse and it's fine. So now I'm worried I have my first electrical gremlin. Does anyone know what could be the problem? When this occured tonight outdoor temp was 7°C I don't know what that is in Fahrenheit but well above freezing. I checked the cable and the rest of the mechanism and it all looks intact.

bhowatt · November 3, 2019

So I'm not sure when it failed but today I wanted to open the sliding rear window, I pushed the button to open the window and nothing... No click from the relay no movement no nothin. I checked the fuse and it's fine. So now I'm worried I have my first electrical gremlin. Does anyone know what could be the problem? When this occured tonight outdoor temp was 7°C I don't know what that is in Fahrenheit but well above freezing. I checked the cable and the rest of the mechanism and it all looks intact.

Did you pull the panel down and check the switch? Maybe the connector came off or a pinched wire? Also did you check continuity in the fuse. Sometimes you can’t see the issue visually

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Canadian GM Guy · November 3, 2019

Did you pull the panel down and check the switch? Maybe the connector came off or a pinched wire? Also did you check continuity in the fuse. Sometimes you can’t see the issue visually

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Going to run out and try that this AM. Where do I pry from?

bhowatt · November 3, 2019

Going to run out and try that this AM. Where do I pry from?

I have not done this specifically myself but I have read it on the forum. There are screws under the sunglasses caddy once removed you should be able to carefully pop the panel down.

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Canadian GM Guy · November 3, 2019

I have not done this specifically myself but I have read it on the forum. There are screws under the sunglasses caddy once removed you should be able to carefully pop the panel down.

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So I pulled the panel down and I can't see anything pinched, when I turn the vehicle lights on the backlight on the switch turns on as well so It must have power. I'm stumped.

bhowatt · November 3, 2019

So I pulled the panel down and I can't see anything pinched, when I turn the vehicle lights on the backlight on the switch turns on as well so It must have power. I'm stumped.

You may have to chase the issue. I would get another person to operate the switch and see if you get power at the fuse panel. If you do check to see if you get power at the window motor. If you do get power to the motor then it looks like your motor is bad. Is your truck out of warranty?

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Canadian GM Guy · November 4, 2019

You may have to chase the issue. I would get another person to operate the switch and see if you get power at the fuse panel. If you do check to see if you get power at the window motor. If you do get power to the motor then it looks like your motor is bad. Is your truck out of warranty?

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I hooked my test light to the fuse socket, it has power. I checked both relays (there's one for opening and one for closing) and they both have power. I checked the switch and it has power and when I toggle the switch power is sent through one of the wires so I'd imagine it works. But when I check the the connector to the motor I got nothing, so I can deduce the motors fine as are the relays and the switch. There's an open circuit somewhere I believe between the switch and the relays because I should hear the relays click when I push the switch and I don't. Does anyone have access to wiring diagrams for the rear window motor system and all components involved?

Canadian GM Guy · November 8, 2019

So I finally caved and took my truck to the dealer, $150 later and the problem is fixed. I'm posting this so you can hopefully save yourself $150 if you experience the same problem I did. Below is what the technician who worked on my truck have to say on the repair order.

****Short to ground at wireless charge module. 1.60 Scanned for codes, no codes. Performed preliminary checks. Tested for switched power, power and ground at relay under hood, has no switch power from switch. Removed switch and tested, switch tests good. Check for power to switch, no power. Traced open to fuse on drivers IP. Replaced fuse and tested several times with no faults. Check for other circuits on F2RL fuse for rear window and found wireless charge module is on the circuit. Check circuit at flex point of harness at console cover lid and found wires broken and shorting to ground. Repaired wires in center console lid for wireless charging. Test wireless charging, working and rear window is moving.****

Essentially the wireless charging pad in the centre console armrest and the sliding rear window are on the same circuit. Over many repeated openings and closings of the lid, one of the wires in the wiring loom that runs into the armrest just wore out and voila. the loom has a Sharp 90 degree Bend in it, and it has to flex in order to open and close according to the technician.

Once I got my truck home, I decided to hell with the wireless charging pad, I don't use it as my phone too big to even fit in it and I don't want the wires to wear out again and cause the same problem. so I took the liberty of disconnecting the wireless charging pad and relocating the wiring loom to the back of the console behind a little cubby hole for the rear seat passengers. I just wrapped it with some electrical tape and zip tied it to one of the other wiring looms.

Here's some pictures for reference in case you run into the same problem. The centre console lid is essentially a sandwich of two pieces. The bottom piece is plastic and the top piece is leather, they're held together with metal wedge style clips. Take a small plastic pry tool and wiggle it in and give it a good pull and it'll come right apart.

davester · November 8, 2019

Thanks for posting this, as it's likely to help someone else in the future (well, hopefully it will). Electrical problems like this suck to find.

But, if you want to save some money and figure out problems like this yourself, I suggest getting a subscription to the full-service manual for your truck. It's not particularly expensive, and has things like the wiring diagram for your truck, where power and ground points are, pinouts on connectors, routing of harnesses, and more. And personally, I find using a more advanced electrical tester (I have an Autel PowerScan PS100) also helps with diagnosing electrical issues, as it can test both for power & ground, as well as a/c, provide power or gnd, test resistance, and comes with a nice long cord (it needs 12V to work, so you hook it to your battery or plug it into the cigarette lighter).

Canadian GM Guy · November 8, 2019

Thanks for posting this, as it's likely to help someone else in the future (well, hopefully it will). Electrical problems like this suck to find.

But, if you want to save some money and figure out problems like this yourself, I suggest getting a subscription to the full-service manual for your truck. It's not particularly expensive, and has things like the wiring diagram for your truck, where power and ground points are, pinouts on connectors, routing of harnesses, and more. And personally, I find using a more advanced electrical tester (I have an Autel PowerScan PS100) also helps with diagnosing electrical issues, as it can test both for power & ground, as well as a/c, provide power or gnd, test resistance, and comes with a nice long cord (it needs 12V to work, so you hook it to your battery or plug it into the cigarette lighter).

Thanks and yeah you're right they do suck. I plan on getting some better gear to test with down the road, thanks for the suggestion. I have a Haynes manual but I don't think it has a lot as far as wiring diagrams go, I'll have to check in the AM.

davester · November 8, 2019

I used to buy Haynes manuals, but after a couple, I realized they are mostly just generic info, with not a lot of vehicle-specific info in them. After getting the FSM for my '04 Sierra (about 5000 pages), while the set of books cost a good bundle of money, it's saved me way more, either in money if I have someone else fix it, or in time trying to fix it blind. Same with tools and equipment, I can pay someone else to use their stuff, or buy it myself and it's generally paid for the first time I use it.

I got the paper version of the FSM, as I don't like using a computer while working on vehicles, but the online version is probably indexed and cross referenced better (as the paper version has me jumping around various spots in the manual doing a repair) and is cheaper up front.

The other thing I would suggest you get, assuming you want to keep your vehicle for some time, and want to fix/work on it yourself, is get a good code reader for it. Not one of those cheap handheld jobs that can read just a couple of systems in the truck, but one that can access all of them. For my truck, I got Autogenuity w gm enhancement, and it can get codes from all the systems in my truck (there's about 15 or so), as well as perform a bunch of diagnostic and repair functions (from injector leak-down tests, to bleeding the abs system, to commanding various components to be on or off (to identify if a problem is before or after the computer, or the computer itself). Main thing it can't do is flash the computers.

Other people have bought the gm tools (tech ii for my generation truck or a little newer, need a different gm device for newer vehicles such as yours), which is really the gold standard.

Canadian GM Guy · November 8, 2019

I used to buy Haynes manuals, but after a couple, I realized they are mostly just generic info, with not a lot of vehicle-specific info in them. After getting the FSM for my '04 Sierra (about 5000 pages), while the set of books cost a good bundle of money, it's saved me way more, either in money if I have someone else fix it, or in time trying to fix it blind. Same with tools and equipment, I can pay someone else to use their stuff, or buy it myself and it's generally paid for the first time I use it.

I got the paper version of the FSM, as I don't like using a computer while working on vehicles, but the online version is probably indexed and cross referenced better (as the paper version has me jumping around various spots in the manual doing a repair) and is cheaper up front.

The other thing I would suggest you get, assuming you want to keep your vehicle for some time, and want to fix/work on it yourself, is get a good code reader for it. Not one of those cheap handheld jobs that can read just a couple of systems in the truck, but one that can access all of them. For my truck, I got Autogenuity w gm enhancement, and it can get codes from all the systems in my truck (there's about 15 or so), as well as perform a bunch of diagnostic and repair functions (from injector leak-down tests, to bleeding the abs system, to commanding various components to be on or off (to identify if a problem is before or after the computer, or the computer itself). Main thing it can't do is flash the computers.

Other people have bought the gm tools (tech ii for my generation truck or a little newer, need a different gm device for newer vehicles such as yours), which is really the gold standard.

Where do you order an FSM from? GM? Or another 3rd party company?