Why does my rear window not work when it’s cold?

[76k5blazerr]

89 Jimmy. I have had this problem the entire time I’ve owned the truck, about 4.5 years. Whenever it is below about 45 degrees I will go to roll my rear window down and it will move about a 1/2 inch and then quit, and not go up or down, but when I hold the switch in either position, my volt gauge drops down like something is happening, but it isn’t. Usually after I let it sit for 10 mins or so, or literally sit there hitting the switch repeatedly it will eventually roll down and back up at normal speed. So obviously this is an issue in the wintertime. In the summer it works just fine. As far as I know the only “mods” that have been done to any of the wiring to do with the rear window is it’s wired to a different 3 position toggle switch below the dash because the OG stopped working, and the tailgate up/down safety switch has been bypassed. The cable is properly lubed and the motor (when it works) goes at normal speeds. Also I have no issues in any temperatures with my front windows. Any ideas? Going on a family trip this weekend and we all might be taking the J because it is supposed to be snowing at our destination. Would love to fix this issue before I have to load an entire families worth of luggage through the passenger door.

 

[ktmoutfront]

Cable needs to be cleaned. To much lube will be cold and stiff (first time anyone has said that). To many people think that greasing the cable is a good thing.

 

[76k5blazerr]

Cable needs to be cleaned. To much lube will be cold and stiff (first time anyone has said that). To many people think that greasing the cable is a good thing.

It’s a new cable within the last year. And I don’t grease it, only use cable lube. I appreciate the idea but I don’t think it has anything to do with the cable. Since it eventually will go down just fine. It’s not like it struggles to move, it just won’t move, until it does. I sure think it’s an electrical problem, I just don’t know what to check first. Is there a relay somewhere in the tailgate harness that could be going bad and not wanting to perform in the cold?

 

[ktmoutfront]

Then the cable is not the issue. No relay in the factory harness. What you are describing could be bad switch contacts. Does it do with both the gate switch and dash switch?

 

[76k5blazerr]

Then the cable is not the issue. No relay in the factory harness. What you are describing could be bad switch contacts. Does it do with both the gate switch and dash switch?

Yes. Doesn’t seem to make a difference which switch you use, and when the window is working, both work fine. Maybe cleaning and reapplying dielectric grease to all of the connections in the tailgate would help?

 

[p0ps45]

It sounds like your window motor may be the issue. See this https://ck5.com/forums/threads/proj...tions-and-upgrades.317811/page-2#post-3478134
There is a PDF linked on how to clean and lube the motor.

 

[Blue85]

The fact the volt gauge is moving proves that power is getting to the motor. So the switch at least partly works all the time. If it's always sticking about 1/2" down, there is likely something with the track, rollers or mechanism at that spot. If it was the cable, it should stick every 1/2" or something like that. How old are the felts and the window seal? Have you pulled the cover to watch it going up and down?

The backup plan for these is to push or pull the window by hand while turning the rear keyswitch. In my experience they do run slower in cold weather. It helps a lot to have the engine running.

 

[76k5blazerr]

The fact the volt gauge is moving proves that power is getting to the motor. So the switch at least partly works all the time. If it's always sticking about 1/2" down, there is likely something with the track, rollers or mechanism at that spot. If it was the cable, it should stick every 1/2" or something like that. How old are the felts and the window seal? Have you pulled the cover to watch it going up and down?

The backup plan for these is to push or pull the window by hand while turning the rear keyswitch. In my experience they do run slower in cold weather. It helps a lot to have the engine running.

It’s not sticking anywhere. The tracks are clean, when it works, it goes down fine, even in the cold. It’s definitely an electrical issue happening when it’s cold. I think I will start with unplugging and cleaning every connection that I can find in the tailgate.

 

[diesel4me]

There may be quite a bit of voltage drop seeing how long the wires that go to the tailgate motor to the switch are....old wire can get corroded in one spot somewhere or its whole length and act like a resistor--and at connections,and after attempts at using the motor it may draw less amps and finally be able to run the motor strongly enough to pull down the window..

We sold many power window motors at the junkyard,for older cars no other yards had any of..often they "worked when parked" but after sitting decades out in the weather many needed to have the gear case opened up and the old petrified grease removed and replaced with fresh grease,and we'd sand the commutator on the armature to ensure it made good contact with the brushes,before they would run strong..that got most of them working better than new..

We always tested them on a battery first..if they worked ok after the "tune up" but still acted sluggish in the customers car,we usually found another problem like a bad or corroded ground,old gangrene wires,etc..some motors we added a ground wire from the motor case to a good ground on the door helped a lot..

 

[Stephen]

I dealt with this a lot growing up in a '82 K5 in Colorado. Clean and lube everything lightly. It seems like the track and rollers would give us problems if there was much for grease in there at all. I'm pretty sure there's a circuit breaker in the power wiring somewhere and that's what's causing it to go down a little way and stop. There's basically too much resistance when it's all "cold" (45 degrees isn't really) and it's blowing the breaker. Replacing the breaker could be a thing to try. It's old and may not be holding well. If I was in the 80s knowing what I know now, I'd run a big power cable back there and either feed it with the factory switch wiring or use the factory switch wiring to fire a relay to operate the motor. Provide multiple ground paths and maybe a dedicated ground wire going up to the front. You may notice the window works better when the truck is running and that's because you're giving the system a couple extra volts from the alternator working for you. I guess measuring the voltage drop at the motor on a cold day would tell you what kind of difference that could make.
So basically make the mechanism as easy as possible to move and optimize the motor power.

When all else fails have someone help the window up and down manually.