Inoperative windows seem to be an on going problem and this fix doesn't seem to come up during a search. Here is how I repaired mine and it was free.
I had a problem on my 99 C5 passenger window, inop in the full up position.
The IPC showed fault codes for the left and right door modules. The volt
meter showed a voltage drop when the switch was pressed but indicated a reading longer in the down mode.
The dealer said that it needed a new regulator as the gears were broken in the gear box. I knew this wasn't the problem as I'd already check that part. I didn't need any parts and I think I found the problem.
The up travel stops in the regulator were at full travel
(by the vender?) which allowed the motor to go beyond the full up position. The motor was cable bound because the regulator was in the beyond full up position which over loaded the motor so it wouldn't operate (thermal switch?). The spring on the cable sheath was coil bound on the regulator and I had to take the case off the motor and turn the armature to relieve the bind.
Vol. 3 chapter 8 in the shop manual didn't cover the adjustment of the up stops. The window glass is held in place by two clamps and the up stops are just below these clamps that are attached to each regulator cable assembly. The glass in the full up position is adjusted to fit the window opening with the clamps on the regulator. This window was moving much higher into the weather striping at the roof then on the driver side. I adjusted the regulator stops and the system has operated properly for over six months now. The below is from memory

1. remove the door handle and panel.
2. remove the window glass (loosen bolt at each clamp).
3. remove the motor and attached regulator.
4. free the bind. Check the motor operation and gear box.
5. assemble and adjust up stops and glass.

To test, the motor reverses by switching the hot lead and ground.
There is a service buletin on dry weather striping over loading the motor.

Good luck, Curt

 

Hey Curt, thanks for this post, just found it doing a search for my pass side window motor inop. Mine actually jammed after a day at the track, I guess some hard launches caused it? I pulled my door panel and gave the motor a couple sharp raps with a screwdriver handle and it started working again. I'll see how long before it happens again...
Matt

 

Sometimes a good whap with the palm of your hand can free the window too... to the upper right of the speaker grill on the passenger side, upper left if it is the drivers.

Mine will occasionally bind up if I don't use the window for a while.

F

 

I had the same trouble with my pass side window. I picked up a new unit and after removing the old one and carefully examing it, I discovered that the reason mine had quit was that one of the cable springs was binding up because the small blue guide that keeps the spring straight, had broken in half. Thus the cable and spring were allowed to kink at 90 degrees. The motor could not overcome the kink and I had a stuck window. The only fix was to replace the cable with the blue guides and springs included. I got one of these from a used unit with bent tracks... now I have a spare.

By the way, thanks Gene at Fred Beans Pontiac for supplying the new one at dealer cost