Rear passenger window will not roll down
I have 2006 Gmc Sierra crew cab. Rear passenger side
window will not roll down by using driver side switch or
rear passenger side switch.
Well, you've eliminated the switches. It could be an electrical problem in the door. Might be the motor or the wiring. If you can hear the motor struggling, it could be a defective regulator or binding glass/track.
Check wiring in drivers door, where it transitions into body. Have to remove boots on door and body, look for broken wires. Wires are rather tight and break from opening and closing door.