'85 Suburban Rear window won't raise

[JohnnysCamaro]

Hello all.
My liftgate window is stuck in the down position. Switch works, liftgate closed sensor switch works. When I press the Window up switch, the voltage dips (lights dim, ignition buzzer drops, you can tell there's a load on the battery, the lift motor sounds like something is gonna happen but the window doesn't raise.

If you slam the liftgate hard with both hands on the right SOMETIMES the window will raise, but won't raise anymore. I've read others on this board who've said if they go over a bump or kick the tailgate real hard in the area of the lift motor it will raise but so far mine isn't doing anything but aggravating me. LOL.

I removed the upholstery cover and metal panel and saw the window, motor, lift arms, etc. I sprayed crank creep through a skinny barrel and tried to lube up the gears, etc. to no avail. My guess is that the grease is so caked with dist and dirt that it's finally quit. One thought I had was to hook up my jumper cables to my newer suburban and see if the extra shoot of electrical juice might break the motor loose. I have even sprayed Electrical contact cleaner through a skinny barrell on everything I can see.

If that fails whats the best way to raise this piece of glass?

THanks all,

Jonathan Smith
Greensboro NC

[johnwaynejeep]

I had the exact same problem with an old wagoneer of mine. The problem was a combination of just and dirt, corroded connections, old sticky window rubber and a weak motor. All of these combined to create so much resistance to the window moving that the old motor couldn't move it anymore.

If you want to get the window up, disconnect the factory wiring from the motor and run 2 wires from the pos/neg side of the window motor out through the access panel so you can get to them, make sure they won't get pinched by any moving parts. close the door and use another battery to just manually apply electrical signal to the motor to get it to roll up, if the motor tries to roll down more, you can just swap the leads to the battery and it should roll the other way, if the components are really dirty, you may have to grab the window and pull it up to help the motor overcome the resistance that it's fighting.

If you want to fix it, then you'll have to take everything apart, clean and lubricate the scissor mechanism and metal tracks, get new window rubber all around, including the window felt that fits in the track around the top edge of the window. Install a new motor and reterminate the window motor wires with fresh connectors. If the motor grounds through the body and the body is heavily rusted, then you may want to run a dedicated line from one of the window motor mounting bolts to a good ground source. there's probably also connectors under the body along the frame to make maintenance easier, disconnect these, clean any corrosion, spray them with a good dielectric grease and reconnect. This should fix any issue which is adding to the resistance of the window moving in the track and your new motor should have no problem getting it up and down.

It may seem like a lot of work, but if you put bandaid fixes on everything then the window will ALWAYS be an issue and you'll be in there every week putting a bandaid on something else, if you do it right, then it will work for another 20 years without any problems.

Check where the wiring goes into the tailgate also, sometimes the constant moving will wear a whole in the wiring harness and start to expose bare wire. I actually caught my Wagoneer on fire one day and that's when I finally took it all apart and fixed it properly.

[JohnnysCamaro]

Hello JohnWayneJeep,
Thanks for your thoughtful reply. There is no substitute for doing the job right. I don't know the Wagoneer's window guts look, but on the Suburban with the window in the down position, the glass completely covers the motor, scissors, wiring and connectors. I am scratching my head about how to connect clean wires to the lift motor and a new battery. THere doesn't seem to be any other way to access the guts unless the window is in the up position.

THanks,

Jonathan Smith

[johnwaynejeep]

JohhnysCamaro,

Now that you mention it, I do kind of remember that from the Wagonner too. this may be how I found another connection in the wiring harness to begin with. There's most likely going to be a connector under the rear bumper where the wiring harness reoutes through the body and under to the frame. this is a good point to connect battery leads to get the window to try to move. I'm not familiary with the safety switch in these, but it should be some kind of plunger, or button that gets pushed in when the tailgate is closed, you can push that in to trip the safety switch so you can roll up the window with the tailgate down. I would suggest having someone else available to support the weight of the window, help pull the window out if there's too much resistance and to tell you when to stop so you don't drop your glass all over the driveway. From here you can access the motor and put in your temporary wires and then roll the window back down and close the tailgate and access the motor manually.

Before you connect the battery to the connector under the body, I would suggest using a multimeter to test which lines are hot (or which lines are grounded depending on how the system is wired) when you hit the window switch. This way you know exactly where to go instead of blindly applying power to various wires.

[JohnnysCamaro]

Thanks JohnWayneJeep for your thoughtful additions. I should be able to find a place in the cable, beneath the tailgate, into which I can splice wires leading to a fresh battery. I was wondering, am I using an external new battery with direct wires into the lift motor to eliminate all the unknown variables, such as weak dashboard switch, possible chassis shorts or other hot wire "bleeds"?

I looked up Salcha, AK on Google Maps. You are way, way up there. I imagine your K2500 4WD plow truck gets plenty of use. 10 years ago, my son and I had a 1974 International Scout that would pull down a barn. We looked and looked for a plow but never found one. Son got married, now has 3 littles, but we still browse the boards for an old IHC. Fond memories.

Thanks again,

Jonathan Smith

[xRAY76]

i had an 85 suburban with this same problem, but it seemed like if you tried the window from the outside with the key, it would work...just to get it up for an emergency.

i never did find out the actual problem, so im not much help

[burban nate]

I have this same problem with my '87 every spring when I get it out of storage. I have to play with the limit switch inside the passenger side latch it seems like that gets corroded. I usually push it in with my finger and use the key to run the window up about 4" then I'll slam the gate hard and make sure both sides latch tight and it will usually work the rest of the year.

This is why barn doors rock!

Nate

[johnwaynejeep]

Originally Posted by JohnnysCamaro

I was wondering, am I using an external new battery with direct wires into the lift motor to eliminate all the unknown variables, such as weak dashboard switch, possible chassis shorts or other hot wire "bleeds"?

I use a stand alone battery exactly for those reasons. It eliminates everything that's not necessary. If you're in cab switch works, then it would be easier and faster, so you could try that first and see what happens. Applying power directly to the motor also eliminates any safety switches that might be faulty. I suppose if you go directly to the motor, you wouldn't need to trip the safety switch like I said earlier.

Salcha is definetly a nice place. My neighbors are nice...and far away. and I can shoot squirrel in my front yard. I wish the truck got more use, but right now it's a project under way, I hope to have everything fully functional by the end of winter...I know, my timing is a little off .

[JohnnysCamaro]

Thanks Nate!

[JohnnysCamaro]

I'd love to shoot a squirrel in my front yard. The last time someone tried to shoot a squirrel for raiding someone's bird feeder, the irate neighbor rushed outside, in bathrobe, bearing arms; he aimed his .22 right between said squirrel's eyes and dropped him to the ground. At that same moment, a bunch of tree-hugging joggers ran by, witnessed the incident, dialed 911. In 4 minutes two cops are in the guy's front yard. I yelled across the street and asked if he was ok, his reply, I'm fine, the neighborhood's all safe now. Lol.

[1Bad65GMC]

If your voltage gauge is dropping and lights are dimming you are looking at mechanical resistance, not electrical. Look at your channels, check window alignment with channels, make sure the regulator is clear of debris, make sure it is not binding, etc.

[JohnnysCamaro]

Thanks. Thats reassuring in a way. At least its not electrical. When that darn window is down there's not a whole lot of room to wiggle around. I'd like to be able to figure out how to grab hold of the bottom of the glass and tug up on it while the switch to the motor is on. I'm tempted to go prowl the junk yard and look for a pair of old barn doors and be done with this. Thanks a million. JOnathan Smith

[1Bad65GMC]

If you swap to barn doors you will need some other pieces. I read up on it here when I thought of doing it with my old 89 Suburban.

Try dropping the tailgate, taking off the access plate. Lock the locks on both sides of the tailgate, this should trigger the switches that normally wont allow this. With assistance from someone else have someone hit the switch while you support the glass. If it comes out than the motor and electrical circuit are working. The other option is take the access plate off and have someone hit the switch while you lay in back and fiddle with it. Be careful where you put your fingers. You can loose them if not careful.

Another thought. Make sure your tailgate is aligned properly when closed. The glass may not be going into the channel up top.

Make sure all your guides are good and aligned, not causing binding.

[JohnnysCamaro]

thanks 1Bad65GMC - i'm sure it is jammed somewhere somewhere i read that there is a window down all the way sensor that tells the motor to quit when the glass is lowewrd enough. if its busted then the glass might go too far down thats what im guessing has happenes.

i found two barn doors that i couldnt pass up at a local junk yard so i bought them i'm going to search and see if i can find that thread you referenced

wish me luck

jonathan smith

[mcrich65]

Hey i have some what of the same problem. I have a 89 GMC Suburban and it been sitting up for about 10 years. I've got her back on the road and has all the Windows down enjoying the day. But when I got home none of the Windows would go up........ I changed the fuse and tried raising them at each door. Still nothing....any ideas????????

[mcrich65]

I'm looking to buy and rebuilt my rear window motor. I open mine up and it fell apart in my hand. If anybody has one to sell please hit my up it doesn't have to work just be complete.