Window regulator, Window motor

November 16, 2015
Window regulator
Toyota gear-drive-type window regulator

The mechanism that moves the window up and down is called the window regulator. In cars with power windows, the window regulator is powered by an electric motor, called the window motor. In some cars, the window motor comes with the window regulator as one unit; in others, the window motor can be replaced separately.

There are two basic types of window regulators: the gear-drive type (in the photo) and the cable type (see photo below).
In a typical sedan, there are four window regulators; one inside each door. In some convertibles, a separate window regulator can be installed inside the rear quarter panel. A window regulator doesn't need any maintenance or adjustment. If it fails, the failed part or the whole unit must be replaced.

Window regulator
Ford cable-type window regulator

Window regulator problems

Problems with window regulators are common. A broken window regulator cable can cause the window to jam or fall down inside the door. See this example, where the cable broke and the power window stopped working.

In cold temperatures, the window can freeze in closed position. When the window switch is operated down, the window can separate from the window regulator. If this happens, in some cars, the window can be re-secured without replacing parts, in others the window regulator might need to be replaced.

Symptoms of a bad window regulator

- the window falls down inside the door
- abnormal noise when a window is moving up or down
- the window rises slow, jams or doesn't close fully
- the window slides up or down crooked
- the window doesn't move at all while all other windows work
- when the window switch is pressed, the window motor runs but the window doesn't move.

How the window regulator is diagnosed

Before deciding on a repair option, the problem must be properly diagnosed. Your mechanic may have to take the door cover off and check what part has failed. If the window motor doesn't operate at all, while other windows work, the window motor electric circuit must be tested to isolate the faulty component. It could be a bad window switch, problem with the wiring or connector or a bad window motor. See how the window motor is tested on the next page.

Window regulator replacement

Replacing the window regulator is not very expensive ($50-140 labor, $40-$180 part) and aftermarket parts are often available. As a DIY project, the window regulator replacement rates from 5 to 7 on the scale from 0 to 10, 10 being the most difficult. You might need to enlist one of your friends to help, as the glass needs to be held in the top position while the window regulator is replaced.

It's also very common for door cover clips to break whenever the door cover is removed. You may want to order a couple of new clips. Typically, there are 8-10 clips holding the door cover.

Read about resetting the AUTO-UP function and testing the window motor on the next page.

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