How to Troubleshoot Power Windows

Many vehicles with power windows have the convenience of a master control switch at the drivers side that lowers or raises windows, and possibly an extra switch that disables individual window control switches. The control circuit provides a reversible motor--and usually a relay--plus a fuse or breaker for each window circuit, in addition to the general relay and circuit breaker or fuse. This setup allows other windows to operate even when electrical or mechanical problems disable one of the windows. These steps will help you locate the problem, whether one or all the power windows in your vehicle seem stuck. You need very basic understanding of electricity or the desire to learn basic troubleshooting procedures.

Instructions

1

Turn the ignition on but dont start the engine. Operate the windows from the master control switch. If none of the windows work, check the main fuse or breaker for the whole power window circuit. If only one of the windows is inoperative, go to Step 3.

2

Check the main circuit relay using a test light. If voltage is coming out of the relay, there is an open or short at the wire feeding power to the other switches. If no voltage is coming out of the relay, use the test light to make sure voltage is reaching the relay. If voltage is reaching the relay, replace it. If there is no voltage reaching the relay, there is an open or short at the wire between the relay and the main fuse.

3

Check the circuit fuse or breaker at the inoperative window. If the fuse or breaker is okay, go to the next step. If you can hear a humming sound as you press the switch but the window does not operate, either the motor is bad or its gearbox may have broken teeth. Go to Step 7.

4

Turn the ignition on but dont start the engine. Using a multimeter, check the master control lockout switch for continuity. If there is no continuity, replace the lockout switch. With some vehicle models, problems at the lockout switch can cause both rear windows to fail.

5

Try the switch at the inoperative window and check for continuity using a voltmeter. If there is no continuity, replace the switch.

6

Check for voltage at the switch using a test light. If voltage is not reaching the switch, there is an open or short between the incoming wire and the fuse or breaker for that circuit power window.

7

Take off the trim panel from the inoperative window. Check for voltage at the motor with a test light while pressing the switch. If there is no voltage, there is a short or open at the wire between the switch and the motor. If the circuit is equipped with a relay, test for voltage reaching and coming out the relay. Make sure the relay is working properly. If voltage is reaching the motor, go to the next step.

8

Detach the window from the regulator and inspect the regulator mechanism by moving the window up and down by hand. Make sure nothing restrains the mechanism. Also, inspect the motor gearbox. Replace any parts as necessary.