Troubleshoot Power Windows

Power windows are standard equipment on most late model cars. Usually the windows cause few problems, but sometimes they can stop working, or fail to roll back up after being lowered.
Problem: One Power Window Does Not Work (no noise, no nothing)
If one power windows fails to move when you press the switch to lower it, the most likely causes would be a bad switch, a bad power window motor, a fault in the wiring circuit between the door switch and the door motor, or a wiring fault in the motor power or ground circuit.
To diagnose this kind of fault, start with the switch since that is usually the easiest component to remove and check. Many power window door switches simply pry out of their fixtures in the door panel. The trick is to pop out the switch without scratching or damaging the door panel. Use a flat, dull butter knife to slip under one edge of the switch, then gently pry up to loosen the switch. If the switch doesn’t budge, it will probably be necessary to remove the door panel to check it.
Once the switch is out, or the door panel loose so you can get to the wiring under it, use a voltmeter to check for voltage at the switch when the ignition is on. No voltage? Then the fault is in the power supply circuit wiring or a wiring connector somewhere between the fuse panel and the door switch.
If the switch is receiving voltage, but the door motor doesn’t do anything when the switch is pressed, the problem could be a bad switch or a bad power window motor. Use a fused jumper wire to bypass the switch and route power directly to the motor. If the window now moves, the problem is a bad switch. Replace the switch. If the motor does nothing, the problem is a bad motor. Replace the power window motor.
If there is no voltage to the switch, the problem may be a broken wire in the bundle of wires that pass between the door and door jam. This wiring bundle undergoes a lot of flexing every time the door is opened and closed, and it is not unusual for wires to break or short out in this area. Open the door and visually inspect the wiring harness that goes between the door and door jam for chaffing or signs of damage. Try wiggling the harness while pressing the power window switch (key on) to see if the window works or works intermittently (which would tell you the fault is in this area).
Problem: One Power Window Does Not Work (you hear motor noise, but nothing happens)
If you hear motor noise (humming or buzzing) from inside the door, but the window does not move when you press the switch, the problem is not the switch, motor or wiring. The problem is a broken window mechanism inside the door.
Some power windows use a scissors linkage with a crank mechanism to raise and lower the window. If the linkage is rusty, jammed or broken, it can prevent the window from moving and/or cause it to stick (up or down).
Other power windows use a plastic chain or strip to raise and lower the window linkage. Over time the plastic window drive becomes brittle, and cracks or breaks. This prevents the window from working. This type of failure often happens during cold weather, especially if ice has frozen the window shut and the motor tries to force it open. The fix is to remove the inner door panel and replace the broken plastic chain or drive strip.
Some windows use a steel cable to raise and lower the window. If the cable breaks or the drive mechanism inside the motor strips, the window can fail to move. With this type of setup, you usually have to replace the entire window regulator mechanism. Same for gear drive regulators.
If the window lowered fine, but fails to come back up, it may be off the track inside the door. This will require removing the door panel to see if the window tracks or guide bushings are broken.
Replacing a Power Window Motor
Replacing a power window motor is not fun because you have to remove the inner door panel. Some door panels just pry loose from the doorframe, but many require special tools to release the clips that hold the panel in place. The best advice is to look up the door panel removal procedure in the OEM service literature so you can remove the door panel without damaging anything.
Once the door panel is off, you may have to drill out rivets that mount the motor to the door frame or window mechanism. This can be difficult depending on how accessible the rivets are. The replacement motor will have new pop rivets or screws to hold the motor in place.
Problem: None of the Power Windows Work
If none of the windows will move when you press their switches, the fault could be a blown fuse for the power window circuit, or an open or short in the wiring circuit that supplies the power window circuit.
Check the fuse first. Refer to your owner’s manual for the location of the fuse panel (usually located under the dash on the driver side, on the driver’s side kick panel, or on a side panel in the center console. Locate the numbered fuse that corresponds to the power window circuit, then pull out the fuse to see if the wire inside has burned through or is broken.
If the fuse has blown, there is either a short or an overload in the power window circuit. Try replacing the blown fuse with a new one (make sure it has the SAME amp rating as the original, not lower, not higher). Then turn the ignition key on and try to lower one of the power windows.
If the new fuse blows immediately, there is a short in the wiring that will have to be found and fixed. DO NOT try to install a higher amp fuse or bypass the fuse for the power window circuit, as this is your only protection against a dangerous overload that could start an electrical fire!
If the windows work, it may have been a temporarily overload that caused the fuse to blow. Trying to lower a window that is frozen shut in the wintertime can do this and/or break the window mechanism inside the door.
If the fuse is okay, there may be a break in the wiring that routes power to the power window motors and switches. You’ll probably need to look up a wiring harness diagram for your vehicle to identify and trace the wires in the circuit.






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