Power REAR WINDOW, Suburban Tailgate & Blazer Troubleshooting

[havaduner]

OK, new to this forum, and like others, I am having issues with my windows on my Suburban. They all work, (barely) except the rear window. Yesterday, I had it partially down, and stopped it there. Now it wont go up or down. Once before if it was down, I could "help" it up with one hand, while using the key switch on the tail gate. Now, nothing. I read in this thread there may be relays inside each door?

 

[HotRodPC]

Welcome to GMSB Matt. Figured since it's the rear tailgate glass and it's a total different animal than the side roll up windows, we'd just start it's own thread.

So if nothing is working at all now, it is possible the motor went **** up. Could also be a ground. I'm not aware of any relays in the tailgate itself whatsoever.

Do you even hear any humming at all as if it's trying? Sometimes the motor can be working but the cable is broke. The rear window regulator operates more on like a speedometer cable than gear to gear like the side windows do.

If the cable is not broke and the regulator is in working order but motor or electrical is failing, then you can jump over the seats get back there and pull the cover off the tailgate. Then disconnect the cable at the motor. Use a cordless drill on the cable to roll the window back up until you figure out what the electrical issue is.

 

[Snoots]

The first thing you should try is to add a heavy ground wire from the frame to the tailgate shell.

 

[gmachinz]

Those rear motors are an older, self grounding style. Typically its a ground problem-the power is carried along the frame with the tail light run and is 12ga orange and light blue. This comes directly from the dash switch-there are no relays from the factory although they can be added.

 

[havaduner]

Thanks for the replies. It isn't making any noise or anything, and I don't see lights dimming when I hold the switch. I'll get back there and pull the inner panel off and see what I can find, and at the very least, I have a way to get the window back up while I try and get it figured out. Thanks again!

 

[PrairieDrifter]

I’ve had problems with my tailgate safety switch. The switch that shuts off power to the window when the tailgate is open. It’s been working intermittently.

 

[86suburban]

I’ve had problems with my tailgate safety switch. The switch that shuts off power to the window when the tailgate is open. It’s been working intermittently.

I was having the same issues with my rear window. I put in a jumper to cancel out that rear safety switch and replaced the electrical connections on the lock cylinder and mine started working again.

 

[TubeTruck]

*cough* Barn doors don't have that problem *cough*

seriously though, check and add ground straps, solves a lot of problems in these trucks

 

[Backfoot100]

*cough* Barn doors don't have that problem *cough*

seriously though, check and add ground straps, solves a lot of problems in these trucks

LOL....agreed..
And I've had both.

It probably wouldn't hurt to open up and lube that whole mechanical nightmare back there either.

I remember having to go through that fire drill pretty much as an annual maintenance thing with my 88. It still wasn't enough living in the rust belt.

 

[jtridgley79]

No cable on suburban. Motor on regulator like door.

Sent from my SM-J727VPP using Tapatalk

 

[HotRodPC]

No cable on suburban. Motor on regulator like door.

Sent from my SM-J727VPP using Tapatalk

Good to know, thanks for the update.

 

[bucket]

There's a relay that supplies power to the dash switch, it is energized when the ignition is on. The key switch has it's own power source. There are three wires going to the tailgate, one up and one down wire (from dash switch) as well as the power wire to the key switch. Inside the tailgate and on the right side latch is a safety switch, it interrupts the "up" circuit when the tailgate is open.

The safety switch is failure prone, it really should be bypassed, just use good sense when closing the tailgate.

The motor can get week over time, it will be amplified by a regulator that is rusty or dirty.

In the land of corrosion, 3-wire harness plug under the back of the rig can turn into a big ball of non-conductive green stuff. If it gets bad enough, the window can fail to operate completely, no matter which switch is being used.

 

[Snoots]

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[bucket]

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My thoughts exactly

 

[Snoots]

The safety switch is failure prone, it really should be bypassed, just use good sense when closing the tailgate.

Is there really any left?