How to diagnose and fix power window not working
Power windows not working?
When you have a power window not working condition, most DIYers automatically suspect a bad power window motor. That’s usually not the case. If you have a power window not working issue, the fault is usually a broken window regulator, bad window switch, or a problem in the power window wiring.
Passenger window not working
Most vehicles have a lockout switch on the master switch to prevent passenger windows from opening if the driver locks them out. If your passenger windows don’t work, double check to make sure you don’t have the lockout switch turned on. If the switch isn’t set to the lockout position, then proceed with the diagnostic steps below.
Window goes down but not up or window goes up but not down
If you want to fix your power window you MUST understand there TWO CONCEPTS:
First: All the wiring for driver’s and passenger’s windows runs through the master switch. When passenger windows don’t work, but the driver’s window does, chances are high that you’ve got a bad master switch in the driver’s door or a broken wire in the driver’s door hinge area.
Second: Power window motors only have two wires. When you operate the down cycle on your power window switch, it provides + power and – ground to the power window motor. When you operate the up cycle, the switch reverses the polarity on those same two wires. So if the motor works in one direction just fine, but not in the other direction it’s almost NEVER the motor—it’s the switch.
Power Window goes down but not up
Aside from not working at all, a power window that goes down but not up is the second most common complaint. If you understand the point I’ve made above; if the window goes down, that confirms that wiring to the window motor is good and, in most cases it confirms the motor is good (although rare, sometimes a motor can work in one direction and not the other).
Test a power window motor
Disconnect the electrical connector from the regulator motor. Set your multimeter to DC volts. Connect the red and black probes to the two wires on the wiring harness connector you just removed. Then turn the ignition key to the RUN position. Toggle the window switch up and down. If the meter reading toggles between +12 volts and -12volts, the switch is good. The problem lies in the window regulator.
Power window voltage toggles but window doesn’t move
If you’re seeing the toggling voltage, the problem is in the window regulator. It’s either a bad motor or a broken regulator that’s causing the motor to stall. Reconnect the electrical connector to the motor and try operating the window. If the motor is good, you should see some movement or hear some noise coming from the motor. If you see movement, the regulator is usually at fault. If you have a cable operated regulator, replace the entire regulator.
If the motor shows no movement, it’s probably bad. But again, if it’s a cable regulator, replace the entire window regulator.
No voltage or ground at power window motor
If you don’t see voltage and ground at the power window electrical connector, the problem is either the master switch or a wiring harness issue. Grab a wiring diagram and check for power and ground coming into the master switch. If you don’t see power and ground, head for the wire bundle in the driver’s door hinge area. Since that door is used most often, those are the wires most likely to break due to the constant flexing. If you find an open or chaffing, repair the wire and you should be back in business.
If the voltage does NOT toggle, then it can only be two things: Bad switch or broken wire. Wires break most often in the hinge area of the door.
If you need to replace the window regulator, click here for instructions.
© 2012 Rick MuscoplatPosted on by Rick Muscoplat