How to Find Your Car’s Power Window Relay

Electric car windows

How to Find Your Car's Power Window Relay.Most modern cars are equipped with electric windows, which is a great advantage as the windows can be slowly controlled to rise and fall. However, if the power windows are broken, it would be too bad. Part of the reason is that the power window relay is malfunctioning.

Power supply for car window relay: It is a solid-state (equivalent to a fuse, but can be reset) electrical device used to control overcurrent. It serves as a feedback mechanism, and when you press up or down, the power windows will run.

Press the window control button, and the relay will send an electrical signal to trigger the electric window motor, thereby supplying power to the device. When the window relay is damaged, it may mean that the window is not functioning at all or may not respond when moving.

When locating the power window relay, this process may vary depending on the car brand and model. What are the general steps to perform this operation?

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Here, we first look at the vehicle's user manual.

Common car manufacturers include:

Toyota
Website: https://www.toyota.com

public
Website: https://www.volkswagen.com

bmw
Website: https://www.bmw.com

Mercedes Benz
Website: https://www.mercedes-benz.com

audi
Website: https://www.audi.com

Automobile manufacturers usually provide the most detailed information about the location of fuses. Then search for the fuse box or relay diagram, which will notify you of the destination of the power window relay

In most cases, the power window relay is part of the fuse box inside the car. Most cars usually have two fuse boxes:

Engine compartment fuse box - sometimes located near the battery or on the side where the battery can be reasonably accessed.
In the car fuse box, you usually find it under the driver's seat or near the dashboard.
Check these two fuse boxes and find the correct relay

Relays are usually grouped and placed in fuse boxes, and a chart is drawn for you. Find the power window system relay. The relay that controls the power windows will be marked on the fuse box cover or in the diagram in the owner's manual.

Sometimes the power window relay is labeled with "PW" or "Window". If unsure, relays may also be listed in the vehicle's maintenance manual, which can usually be found online for free.

Newer cars even use electric window control modules, eliminating the need to pull boring cables. This module is slightly more complex and can generate multiple new windows. If you have a control module, the location of the relay or inside the car door can also be that thing. Please refer to the owner's manual to see if there are any methods described so that you can pull it without damaging the control unit.

Electric window button

After finding the power window relay, it needs to be checked. If the relay seems to have a defect, you can try swapping it with similar relays in other systems in the car (i.e. horn relays, which typically have similar sizes and functions). If it starts working, the original relay is damaged.

If there is no backup relay, a multimeter can be used to test the on/off status of the relay. If there is no continuity, the relay needs to be replaced.

If a defect is found in the relay, a new relay needs to be installed. Electric window relays are inexpensive and easy to replace. You can purchase replacement parts from a local car parts store or order them online. Please remember that you need to purchase suitable accessories according to your vehicle model.

Steps for replacing the relay

Turn off the engine and disconnect the battery to avoid electric shock.

Pull the damaged relay out of the slot.

Install the new relay and secure it in place.

Connect the battery and test if the power windows are working properly.

If the problem persists after replacing the relay, it may be due to other components of the power window system. Here are some possibilities:

Fuse burnt out - If there is no problem with the relay, but the window still cannot work, please check the fuses related to the power window system. A burnt fuse will interrupt the current.

Electric window switch malfunction - sometimes the problem lies with the window control switch itself, rather than the relay or motor.

Damaged electric window motor - If all electrical components are functioning properly but the window still cannot be raised or lowered, the electric window motor may have malfunctioned.

William Relay Engineer specializing in writing blog articles on automation equipment electronic components and relay industrial control equipment