How do you test a power window motor to see if it is bad?

I have a 1993 ford taurus 3.8L V6 automatic GL. My rear right side power window will not work. I have tried replacing the switch but it has not solved the problem. How do I test the “power window motor” to see if it is bad?

If there is voltage going to the motor when you activate the switch and the motor does not operate would indicate the motor is bad.

You gain access to the motor wiring harness and apply 12 VDC to see if the motor functions.


Remove the inner door panel. Using a pin probe and a schematic, check for the presence of 12 VDC at the motor when you push the buttom. If you have voltage, the motor itself is dead. If not, check voltage at the appropriate “hot” wire at the button on the driver’s door. If you have voltage there, then you have an open in the wiring harness between the driver’s panel and the RR window. If you have none there, you’ll need to trace back from there.

The circuit itself will be parallel circuits (one for the driver’s door button and one for the passenger’s door button) both running through the driver’s door. The harness runs from the fusebox through “cutouts” in the body into the driver’s door and into the passengers door.

The harnesses usually wear where they go through the door cutouots, where they flex every time the door is opened. Finding and splicing the bad wire requires untying and “breaking into” the wiring bundle, then probing with a meter and a pin probe.

Note: of the motor is bad you may have to buy the whole “regulator assembly”. Many are not made to be repairable.

Good luck.

Many Ford window motors have a gear box as part of the assembly, this gear box has plastic pins that drive the window gear, these are prone to disintigrate and lock up the gears. Take the motor out and there are 3 or 4 bolts that hold the gear box cover, remove these to get to the innards! Of course you could also have a broken regulator, they are cable driven and pure junk. Auto window places have these pins dunno if dealer has them. Good luck, Andy

Make sure on one pin at the motor is 12v (when the switch is pressed) and also of great importance is that there is a full ground on the other pin of the motor, the polarities will reverse when you change the press position of the switch.

I always found a test light that showed both power (with a red LED) and ground (with a green LED) to be very useful in testing both power windows and power door locks.

Yes, it’s more likely to be the regulator or the gear box than the motor.