1999 silverado.
Both power windows worked fine for years. Just this last year both of them decided to move slow and at times not close all the way without assist. In my ford experience the window seal/run was creating to much resistance ( felt all worn off). So I changed the seals on this silverado. Still same. Slow windows.
bought some Doorman discounts off amazon. Still same.
Bought New Doorman locally thinking, maybe the others were returned for a reason ( no were not used). Still slow. Bought NAPA Echillin brand. Better but still struggling.
sprayed some RV window channel stuff in the run. Made it better, until it dried out, then worse. Had same effect on my ford.
so with new OEM seals and new window hardware.. I still can't get them to move at a proper pace. These are not complicated. There is no adjustments. WTH!
I can't be the only person to ever have this problem.
I don't want to grease the seals, I shouldn't have to.


note: the doorman are made with thinner sheetmetal and non factory design. The Echlin is factory design and with bigger motor, just no included bolts.

 

Exactly what Dorman/Echlin products did you purchase?

It sounds like the window regulator motors are getting weak. What you need to do is to replace the entire window motor-regulator assembly with something like this:

https://www.rockauto.com/en/moreinfo...=15596&jsn=673

Good Luck!

 

Just a thought... but I've had electrical issues with my 1996 C1500 a few times. Could you not be getting enough juice (amps) to the motors, which would certainly impact the speed/strength of the motors?

I would check the wiring harness connectors and wires from the motor, all the way back to where they come from the fuses, if possible. I recently had to replace burned up connectors on the wiring harness side of things for my blower motor, my blower resistor, and for the blower speed controls. Not fun having to splice new connectors onto things, but these connectors basically burned up and quit making good connections over 28 years of use.

Both my 1996 and my 2006 pickups have manual window regulators.... I got burned out on bad electric windows back in the 80's I guess!

 

the assembly with motor.

 

yah.. I think that's my next route I need to look at. See what the motors are actually getting.

funny that the one motor was hot and couldn't move worth nothing.

 

Which motor was hot - old window motor, new window motor?

Being hot often means a bad electrical connection. Are the grounds tight? Are the electrical connectors distorted from being overheated? Any melted insulation on the wiring going to the motor(s)?

 

Check electric at motor driver side. I am only loosing about 1 volt. Hard to see in picture but the left side is a bit low, and this is where it really has a hard time pushing up. If I give it a nudge where you see my finger, it goes up cleanly. I can also push on the window to the right as going up and it goes up smoothly.
it's twisting as it goes up. The doorman products were far worse with this twist. Pushing the top left into the seal.
So when I install the motor assy to the window. I push window all the way up. Fully seated and then bring the clamps up to it. Let them seat and then tighten. This is the only spot this can be done. Door inner skin in the way anywhere lower. To low and the window is out of the track.
I may try put a wedge under the left side of the clamp.
I don't know a way to change the cable timing.

 

I am not sure what to tell you. When I replaced the window regulator assemblies (driver & passenger doors) on our 1999 Silverado, I had zero problems, and the the windows went up and down like new.

Have you checked the wiring inside of the rubber bellows between the door and the body for integrity?

 

Yah i dont get the problems either.
wiring is OK. Its not cutting out due to broken wire. It's got good voltage at the motor.
The new Echlin is the one that was getting hot and completely not going up. I returned it.

door frames are not bent either.

 

I ended up sticking a wedge of rubber under the left side of the drivers window. Goes up perfectly now. Ultimately would to fix the timing, but that's more complicated and I rather not. At least the clamps grab pretty high up the glass unlike the doorman product.
the passenger side is still a bit slower than drivers. But it seats in the seal and i am tired of this crap. So yah.
I got some silicone grease I may smear a little on the passenger seal and see what it does.

There was nothing wrong with the old scissor style. Now this crap.
​​crap.the Doorman with its dual springs ( not oem style) definitely moved around allot more. The differences between manufactures and even within are interesting.

Be careful what you get from the store, the opened new I got from Amazon I don't think fuly matched the box.