Window regulator, Window motor

Window regulator AUTO-UP function reset

In many cars, the power window must be reset after the window regulator or window motor is replaced or the AUTO-UP function will not work. You can google the specific reset procedure or check the owner's manual for your car. For example, the Quick Tips brochure for the 2007 Mazda 6 describes the procedure:

With the ignition switch "ON", press switch and fully open the power window. Next, pull up switch to fully close power window and continue holding switch for about 2 seconds after window is fully closed. Repeat the same steps for the front passenger window from the passenger door switch.

How the window motor is tested

Checking the window motor circuit

In this car, the window motor in the right front door stopped working. Pressing the window switch up or down does nothing, however all other windows work. We checked the service manual that says to remove the interior door cover and check for battery voltage at the window motor connector.

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Checking the window motor circuit

The manual says to operate the window switch and check for the voltage at the connector. When the window switch is pressed "Down" the multimeter measures 12 Volts, so we know there is power at the window motor switch.

Checking the window motor circuit

When the window switch is pressed "Up" the multimeter shows -12 Volts, because the polarity changes when the window switch is moved from "Down" to "Up" position.

Checking the window motor circuit

Next, the service manual asks: does the motor operate by connecting the battery voltage directly to the motor? We did it and nothing happens, the window motor is bad and must be replaced.

Window regulator replacement

The window motor comes together with the window regulator as an assembly for this car. The new part was less than $100 and it took around one hour to replace. This post has links to sources offering the service manual online.

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