#car window repair
The most common power window mechanism is pretty basic. There’s a simple regulator mechanism, usually similar to the mechanism used on garden-variety hand-cranked windows. It comes in several varieties–rack, sector and cable drive. Troubleshooting is pretty straightforward, once you get the door panels off–but your problem may be terribly simple and may not require removing any trim at all.
First: Are all of the windows on the fritz? Or just one? If you can’t move any of the windows, the first place to look is at the fuse. Window regulators are high-current devices, and the fuse is sized to just barely be able to open all four windows together. Age and a few sticky window channels can pop a fuse. Turn the key to the Run position, but don’t start the car.
If the fuse is blown, pushing a window button will do nothing at all: The motor won’t groan and the glass won’t quiver. If the fuse is good and you can hear the motor, or the glass acts like it wants to move, then you’ve got some sort of mechanical problem. If not, check the fuse. If the fuse box isn’t labeled, check the owner’s manual to see which fuse is the culprit. Don’t go yanking fuses willy-nilly looking for a bad one–you might interrupt the power to the engine management computer, causing poor driveability for 30 minutes or so–or you might reset all the buttons on your car radio to that undersea-alien rock-gospel station.
Fuse okay, but the window still won’t budge? Again, are all the windows dormant? Or just one? If it’s just one, you still may get an opportunity to go spelunking inside the door. If it’s all four, maybe it’s something simpler you can troubleshoot under the dash.
At this point, if you’ve narrowed the fault down to some electrical problem that’s not as simple as a blown fuse you need to round up a schematic of your car’s electrical system and a voltmeter or 12v test light. All that’s necessary now is to start at the fuse panel and follow the wiring to the switch, and from there move on to the motor, testing along the way for 12 volts. Somewhere, you’ll find a loose or corroded connector interrupting the voltage to the motor. Or, the switch itself might be bad. If the driver’s door switch won’t open the right rear door, but the switch in the door will, look for either a bad switch in the driver’s door or a fault in the intervening wiring.
Carefully backprobe the window switches to isolate any electrical faults in the switches, connectors or wiring.
At this point, you probably need to be able to access the inside of the switch panel. On some vehicles, like the one in our lead illustration, you can simply pry the panel up with your fingers and backprobe the connectors. Other vehicles may require that you remove the panel.
Door panels are held on with a bewildering variety of fasteners. Start by pulling off all of the door pulls and handles. The perimeter of the panel is customarily held on fragile plastic studs intended for one-time use. Pry them up carefully, and you should be able to reuse them.
Once you’ve got the door panel off, carefully remove the weather sheeting. You’ll need to replace this later, and you may need fresh contact cement to do so.
Warning: You now have the ability to put your fingers into places where fingers normally don’t go. As our mechanic pal Lefty points out, “A power window motor has enough torque to put a serious hurtin’ on ya if it’s actuated while errant digits are in the gears.”