Power window regulator — How it works and how it fails

How a power window regulator works and its most common failures

Starting in the early 2000’s car makers switched from a heavy duty scissors style window regulator to a much lighter and less costly cable driven style power window regulator. Where the older scissors style window regulator would normally last the life of the vehicle, the new cable driven window regulators failed within just a few years after rolling off the assembly line. They were simply under-engineered.

Worse yet, the carmakers’ replacement window regulators were no better, so the new regulator would just fail again in a few years.

The most common causes of power window regulator failure

• Poor design
• Moving window when it’s frozen
• Dirt, grit or restriction in the window channel; anything that causes extra load on the motor and cable drive system

Cable power window regulators aren’t heavy duty, so any restriction in window’s movement can cause the winding spool, plastic gears, or idler rollers to break and cause a complete failure. If your windows ice up in winter and you try to operate them, the window clips or the plastic pieces on the regulator can break. Also, if the window tracks aren’t lubricated, the glass can bind on the way up or down and that restriction can stress the cable and cause the unit to break.

One way to reduce the likelihood of breakage is to treat the window channels (the rubber or felt tracks that guide the front and rear portions of the window glass) with a spray lubricant like dry Teflon lube or spray silicone. Click on this video to see how it’s done.

Window moves up or down but not both ways

When a power window operates in one direction, the cause is most often a faulty or corroded electrical switch. The master switch on the driver’s side is almost always the culprit because it’s the most used and exposed to rain and snow when the window is open. Some master switches can be cleaned, lubricated and reassembled, but most must be replaced.

These images show a master switch where the individual switches are replaceable and the corroded circuit board of a master switch.The window regulator is seldom the cause of a power window that opens fully but won’t close, or vice versa.

How much is window regulator repair?

Most window regulators can be replaced in about an hour. Depending on  the labor rates in your area, that can run about $140. If you replace the window regulator with an (OEM) version, the part cost runs between $400 and $600, bringing the total cost to around $725. However, your shop can install an aftermarket parts window regulator for much less. There are some decent aftermarket brands and others that are cheap, but poor quality. Talk to your shop about which aftermarket brands have worked well for them.

©, 2016 Rick Muscoplat