Back window issues

[TheChiro]

Howdy.

I just picked up a 1986 GMC Jimmy. It had been sitting for a few years, so I'm working through some of the ghosts in the system. The back window will no longer roll up or down using the key in the tailgate...Now it will roll down using the switch on the dash. That being said, it will only roll up, if pressure is applied to the tailgate.

There is probably a simple explanation for this...Does anyone have some perspective on this?

 

[Sad Sack]

Howdy.

I just picked up a 1986 GMC Jimmy. It had been sitting for a few years, so I'm working through some of the ghosts in the system. The back window will no longer roll up or down using the key in the tailgate...Now it will roll down using the switch on the dash. That being said, it will only roll up, if pressure is applied to the tailgate.

There is probably a simple explanation for this...Does anyone have some perspective on this?

Sounds like a hunt for wire and connection gremlins.

 

[Chevy 88]

Did it ever work with the key since you have owned it it?

Applied pressure where?

 

[TheChiro]

Did it ever work with the key since you have owned it it?

Applied pressure where?

I just bought it this week and it wasn't working. The previous owner said it used to work. And if I have someone apply pressure on the top rail in the middle of the tailgate, the window will roll up.

 

[TotalyHucked]

My advise would be to remove the access cover, pull the cable out of the window motor, chuck it up in a drill and spin it slowly and watch for any issues. If it moves up and down smoothly, grease the tracks for good measure and then you likely either have a bad electrical connection or a motor on it's way out

 

[TheChiro]

My advise would be to remove the access cover, pull the cable out of the window motor, chuck it up in a drill and spin it slowly and watch for any issues. If it moves up and down smoothly, grease the tracks for good measure and then you likely either have a bad electrical connection or a motor on it's way out

Really appreciate the advice, I’ll definitely do that this weekend and let you know. I’m trying to figure out why holding pressure on the middle of the tailgate helps it work.

 

[Chevy 88]

I agree, pull the cover. My manual window didn't work very well, but grease helped a lot. You probably have some rest/corrosion on the electrical connections. Maybe a bad ground. As for the motor, if its getting weak - you may be able to repair it. Nothing to lose by trying.

 

[TotalyHucked]

Really appreciate the advice, I’ll definitely do that this weekend and let you know. I’m trying to figure out why holding pressure on the middle of the tailgate helps it work.

It just dawned on me, IIRC, the tailgate grounds to the truck through the latches? So pushing the tailgate forward would make a better connection. It acts as a safety to keep from being able to extend the glass with the tailgate down

 

[TheChiro]

It just dawned on me, IIRC, the tailgate grounds to the truck through the latches? So pushing the tailgate forward would make a better connection. It acts as a safety to keep from being able to extend the glass with the tailgate down

Yes! That makes sense. Any tips on ways to improve the connection? Guess it could be more of a tailgate issue.

 

[TotalyHucked]

Yes! That makes sense. Any tips on ways to improve the connection? Guess it could be more of a tailgate issue.

I've honestly never messed with one that had connection issues, it was always either been a dead motor or the window had jumped off the track. I'm honestly not sure if you can adjust the latches any or not. Hopefully one of the Blazer guys can chime in

 

[TheChiro]

I've honestly never messed with one that had connection issues, it was always either been a dead motor or the window had jumped off the track. I'm honestly not sure if you can adjust the latches any or not. Hopefully one of the Blazer guys can chime in

I'll start with latches and I may still swap in a new motor

 

[Cdncarnut]

The left hand latch has a safety switch which prevents the window from being rolled up without the tailgate being closed.
That applies to the dash switch and the key.
As for the window not going down with the key, I have never come across that.
However start with the left hand latch.
I think that I installed a jumper wire on mine.
As the truck has been in my stable for 44 years, I have forgot all the things which I have done to it over the years.