Window Not Working? 9 Reasons Why Window Motors and Regulators Fail
Power windows conveniently open to let fresh air in and enable you to communicate with someone outside your car. But more important than letting you grab your coffee in the drive-thru, they’re an escape hatch if there’s an emergency. With a power window that won’t roll up or down, you’re putting your car’s security and your safety at risk. When a window won’t work with the switch anymore, there could be a problem with either the window motor or the regulator. Why do failures happen, and what causes it?
How Window Motors and Regulators Work
Manual windows aren’t very common on new cars anymore, but there are many on the road with them still. The crank on the inner door panel is turned by hand to move a gear inside the door, lifting and lowering the window glass on a scissor-style regulator.
Power windows simplify the motion. A small electric motor fastened inside your door operates the system when you press the button inside your car, rather than a hand crank. The motor rotates one way to lift the window and the opposite direction to lower it. The motor is attached to cables and a track system that lift and lower the window glass, better known as a regulator.
Some regulators are scissor-style while other are on a geared arm or have a lift plate. Regardless of which design your car uses, the basic structure remains the same.
Some windows will work dependably for the vehicle’s full lifetime. Others, not so much. Heavily used power windows will tend to experience problems more frequently, and drivers in climates that freeze for a serious portion of the year will probably see a higher frequency of issues than those in sunny, warm climates. Why they fail can often boil down to one of these four factors.
Common Causes of Window Problems
Child Lock Button
It might seem like an obvious solution to the problem; however, it’s overlooked quite regularly. The button that prevents rear-seat occupants from opening the windows could be engaged, making for a simple, no-cost repair. Checking this first could save you some effort.
The same type of twisted wire cables that you’d find on bicycle brakes are used for window regulators. As they move over a roller on the regulator, strands of the cable can snap and snag on the channel or jam into the cable’s sheath. This is the type of symptom you’d see from heavy usage primarily.
With one or more strands of cable broken, the window is apt to stop moving at a certain point in its journey up or down. Unfortunately, cables aren’t replaceable individually, so a new regulator is required.
Broken Clips, Guides, or Rollers on the Regulator
Clips that attach the window glass to the regulator can sometimes be part of the regulator itself. Made of white plastic, they can get brittle over time and snap off. When that happens, you might find the window motor still sounds like it’s moving but the glass isn’t going anywhere. Some models have clips that can be replaced individually, but generally, the regulator will need to be replaced.
The same is true for plastic guides on scissor-type regulators that keep the window inline moving up and down, as well as rollers attached to the channel. Most of these guides and rollers can break due to dry channels, and since they can’t be replaced individually, a new regulator is required.
Window Motor Burnt Out
A 12-volt power window motor can definitely move the window glass up and down with what seems like little effort. But add some extra strain and it can struggle. In climates where ice and snow stick around for months, the power window motor can often fail if the driver tries to ‘break’ the window free when it is frozen shut.
Mechanically, the electric motor inside the door is straining against two cables as it tries to pull the window free and overloads internally when it doesn’t succeed after multiple tries.
Window motors can also fail for no reason whatsoever – they are an electrical part, after all. Sometimes it will move slowly before quitting altogether when the motor has been weakened.
Stripped Window Motor
The window motor has a small gear that fits into the regulator. This gear can strip if it’s strained too much, or the clutch mechanism inside the window motor can fail. It sounds like the window motor is still working, but without the gear functioning, the window glass won’t move.
Whether your car uses side channels or a center lift channel, it’s made of metal with plastic rollers that are lubricated from the factory. With frequent use, these channels can lose their lubrication and the motor strains to overcome the extra resistance.
Caught early on, it might be possible to lubricate the channel with white lithium grease or something similar. Otherwise, the cables can cut into the rollers and jam up the window, requiring the regulator and motor assembly to be replaced.
Regulator Gear Damaged
Manual windows may have fewer weak spots, but the regulator gear can still be damaged. It’s possible for the gear to wear down, get stripped out, or have one or more teeth break, resulting in a window that gets stuck or won’t roll up or down.
Window Switch Problems
Although not a part of the window motor or regulator, the power window switch is a related component that could cause window faults. The switch connects a circuit to direct power to the window motor, and if it isn’t making a connection, the window motor won’t engage. Many power window circuits route through the driver’s door master switch, so if a passenger or rear window isn’t working on the driver’s door but it is at the door, it could also be the master switch that is at fault.
Corrosion in Connector
An electrical connection combined with humidity can often generate corrosion buildup. The corrosion interferes with the connection inside an electrical connector, much like if a window switch circuit doesn’t connect. Sometimes corrosion can be cleaned off to restore the window motor’s operation while in other cases it has damaged the connector and wiring, and the assembly needs to be replaced.
Window Motor and Regulator Replacement Cost
The cost to replace a window motor and regulator assembly varies greatly, and it’s based on the make and model you drive. For some cars, the window motor and regulator can be replaced individually, while for others it comes as an assembly all in one. Parts can range from under $50 to hundreds of dollars, depending on the vehicle you’re working on. Labor charges vary as well. While you can expect the repair to take around an hour at least, some models might take two hours or more to change the parts.
In your mind, it might be just an inconvenience if a power window isn’t working. Keep in mind that it’s an issue that won’t pass a safety inspection in most jurisdictions. You can save money by changing the parts yourself when you order from AutoZone, or you can have a preferred installer near you put them in for you.