Intermittent power window problem

I have a 1988 Chevy C2500 pickup that I bought used about 3 years ago. For as long as I have owned it, the driver’s side window intermittently doesn’t function. It only seems to malfunction within a few minutes of starting the truck for the first time (window does not open when you push the button) - a few minutes later, if I try again, the window operates fine, and continues to do so for the rest of the day.



It was worse when I first had the truck (not limited to when the truck was cold, and sometimes the window wouldn’t close, either) and occasionally the passenger window was problematic as well. About 6 months later, the motor burned out with a horrible smell, and was replaced. All seemed OK for a week or two, then back to the current behavior. I can’t remember whether or not we replaced the passenger side window motor at some point, but I haven’t noticed any recent problem with that window.



So, the question is, what is causing this? The improvement with warming up would sure seem to hint at the window motor again, but after only a couple weeks of normal function of the new unit? I had originally thought it was a switch problem, but since replacing the motor, it really only is a problem first thing on starting the vehicle.



I did notice today that the weatherstrip on the inside of the window was tearing off its attachment to the inner door panel and getting pulled down inside the door when the window goes down, so I just pulled it the rest of the way off. Could the increased friction account for the observed behavior?



Any suggestions how to track down the cause of this problem?



Thanks,



Rebeccah

Check the engine to firewall ground wire. It may even go to a fender. Scrape the firewall end once it is disconnected and wire brush the firewall where it connects. A bad ground there could weaken the battery and make the window move slower or not at all.