electric window won't go down

The driver's side electric window on my 94 Grand Prix will not go down yet all of the other three windows work perfectly. How do I know if the problem is with the window switch or the window motor in the door?

If you pull the switch there should be one wire with power all the time. When you push the switch in the down position one and only one more wire should have power to it. Same with the switch in the up position.

If no other wires power up or two wires power up than the switch is bad. If only one other wire powers up with the switch in either position than you can remove the door panel and tap on the window motor while holding the switch in the down position.

If it moves the motor is bad if it doesn't move make sure you have power on one wire at the motor and the other is grounding. If no power or no ground than check the harness in between the door and the a pillar for broken wires.

That should give you a good start.

If no other wires power up or two wires power up than the switch is bad. If only one other wire powers up with the switch in either position than you can remove the door panel and tap

Before opening up the door panel, try holding the switch while closing the door. Sometimes the jarring effect of closing will get it going again.