tailgate electric window

[WarWagon454]

so my electric tailgate window is stuck in the down position. The problem is that you cannot access anything, it is all behind the glass. The interlock switch (the one that keeps the window from opening if the tailgate is down) has been jumpered out previously. I guess that I can hook up a battery to the window motor? Does anyone know which wires to power? There are four of them, and if I blow up the window motor(if its not dead already), then i'll have to cut the tailgate. Thanks!

[Zoomad75]

You shouldn't have to cut up the gate. If the window won't move and you have power to the motor one of two things happend. The motor fried or the gear stripped due to the tracks binding up. With the window down, you should be able to access the regulator with the gate down. To access the regulator behind the glass, just unbolt the glass from the tracks. If I remember it's only 1 or 2 bolts per side. Slide the window out enough so you can get to the motor. Unbolt the motor from the drive cable. Take a portable drill and chuck the drive cable up to it. As long as the gear isn't stripped you should be able to move the regulator up and down. If that works you know the mechanical side is ok and all you need is a motor. If it still won't move with the drill, chances are the cable broke or the gear at the other end of the cable that turns the regulator stripped out. Check LMC or the local dealer for parts. but be aware you might only be able to buy the assembly and not the individual parts.

Which ever you find as the problem, here's my tip to prevent it. While working inside the gate on the regulator inspect the tracks where the rollers slide. If they are rusty, the rollers probably aren't round anymore. Instead of rolling like they should they start to slide constantly wearing one side down flat. That adds resistance to the movement of the regulator and adds more load to the motor and drive cable/gear. My manal glass was so bad on mine you couldn't turn the crank with both hands to get the glass up the last 2 inches. Any more force on mine and I would have broke the handle (easy to do). If you find the rollers wiped out, you can get them from the local GM dealer (have them look it up for a 91 as its easier to find the newest stuff in thier systems, but its still the same part). The rollers come with new rivits and are easy to install with the regulator removed.

[WarWagon454]

The bolts that attach the regulator arms to the window are below the bottom lip of the tailgate access door. So if the motor fries and the window is in the utmost down position, im pretty sure that you're fu#ked. But i'm not 100 percent sure that the motor is fried, so im gonna try to get some juice to it somehow tomorrow. I can probably reach in with a jumper on a hanger or something. Wish me luck. Thanks!

[Zoomad75]

THey may be down below the lip, but you might be able to reach them with a box end wrench. But then again, it's been a couple of years since I had mine apart.

I'd say jumping power to the motor is your best bet right now. I've heard of some guys just using a 12v (or greater) battery from a cordless drill and a couple of jumper wires to power the motor up or down.

Keep us informed of your progress.

[Bad Karma]

Not sure if yours is the same, but on my '77 the tailgate harness has a disconnect just outside of the gate. Easy access to the wires right there. I don't remember what color does what off the top of my head, but a decent manual should tell you.

[TC70C10]

Miine is currently stuck in the up position so here's a couple of things to look at. I got on the site tonite to get some clue that I might be missing and saw your thread. I've been thru this before but it's been a while. Many times a good off road run will fix me.
Here's some things I know from experience and researching my service manual:
1).There are 2 30 amp circuit breakers in the fuse panel. No fuses go to the rear motor. The circuit breakers are supposed to reset but it might be worth a try for 6 or 7 bucks. (didn't fix mine)
2). Check the plugs under the rear tailgate and make sure they're not full of mud or have vibrated themselves loose.
3). Check the tracks that the window slides up and down in that's inside the tailgate. I dug out all of the old felt on mine because it was binding the window on the way up.
4). I think there are only 3 wires that go to the rear motor. I can copy the schematic and fax it to you if you think it will help.

I'll keep an eye on the thread. Good luck.

Tim

[Bad Karma]

Good info! When I was troubleshooting my in-cab switch, there was also a plug in the firewall you can use for wire access.

My window would stick sometimes to where it wouldn't come down. I sprayed white lithium grease on the regulator and silicone lube in the window tracks and now the rear window works perfectly.

[TC70C10]

I guess now I know why they went to the pop up glass over the rear tailgate. Too many problems.

[Bad Karma]

Yup, if I ever get another Suburban, it will have barn doors.

[WarWagon454]

Barn doors are no fun!

-problem solved! Moral of the story: If your window is stuck in the down position, to get at the bolts that hold the window to the regulator, you must first loosen up the tracks and work them until you can press the glass down far enough to get a 1/4" ratchet at the bolts. Then you can disconnect the glass from the regulator, pull it out completely, and work on the motor system freely.

I took almost every bolt out of the tailgate in frustration, trying to get the window out so that i could work on the motor, and then accidently realized that this is what you're supposed to do! Ha. Go figure.

-so ultimately, the problem was that the previous owner, or whoever worked on the window previously, jumpered out the safety interlock switch, and the jumper eventually wore apart, and that was why my window was stuck in the down position. Ha!

-why can't i find the circuit breakers by the fuse panel?

[Zoomad75]

Gotta love the previous owners. Mine only bondo'd the quarters to a 1/4" thickness, butchered the dash for a din size radio and booger welded toyota 4runner seats in all three positions. That and the double fist sized hole in the oil pan!

I would have been happy with a stuck window. At least you got it fixed. Plus you gained knowledge on the crazy backwards engineering GM had at times (plus the worse kind of McGyvering)!

[TC70C10]

I got window down the other night with the drill trick. Need my buddy to come over while we test out the electrical. To hard to hold the voltmeter and hit the switch in the front of the cab.

Their should be two circuit breakers in the fuse box. Their about 3/4 inch wide and 3/8 inch high. They plug in like the plastic 20 amp(etc.) fuses.

TC