Common Electric Window Problems & Solutions

Window regulators are the mechanisms that allow the occupants of a vehicle to raise and lower the windows as required. The majority of cars today have electric windows allowing the occupants to raise and lower the glass using a switch. These can become worn and damaged over time. The
following guide will help in figuring what exactly needs to be fixed or replaced.

Driver Side Windows are checked during the NCT (National Car Test). They can result in an NCT failure for the following reasons:

1. Insecure.
2. Opening mechanism of driver’s window not operating.

Source: http://www.nct.ie/

Signs of a malfunctioning window regulator:

1. A window does not go up or down when buttons are pressed.
2. Operating the window makes an unusual or loud sound.
3. Window drops to one side.

If the window regulator needs to be replaced, enter your registration number on our Window Regulators page and hit Go. Then use the filtering options on the left hand side to filter for the regulator you need i.e left or right, front or rear.

Did You Know?

Electric Window Lock Button

Almost all cars with electric windows have a lock button that cuts power to all windows apart from the driver’s side for safety reasons. It's worth checking if this button has been pressed accidentally.

When testing the windows, use both the drivers side master control switch and the switch at the malfunctioning window.  If one of these switches operates the window as normal, then we know that there is a problem with one of the switches.

There are 4 main reasons for a malfunctioning electric window.

1. Blown Fuse 
2. Faulty window switch
3. Faulty window motor
4. Faulty window regulator

If you can hear the motor running (a humming sound) when you press the buttons to operate the window, then you can rule out a faulty window switch and a blown fuse. You should skip to checking the motor and window regulator. If you can't hear any sound when you press the buttons then it's time to check the fuse.

Blown Fuse

If all the windows have stopped working then the most likely cause is a blown fuse. The location of the fuse box will be in the owners manual or Haynes Workshop manual. You may need a flat head screwdriver to pry open the fuse box cover. In most vehicles, there is a diagram on the inside of the cover which illustrates the location and purpose of each fuse. 

Testing a Fuse with a Voltmeter

           Testing Fuse with Voltmeter     Source: http://kzcarfi.blogspot.ie/

The safest method for testing a fuse is to use a voltmeter (or a multimeter that is set to Volts). Turn your ignition to the on position and clamp the negative (black) lead to a ground. Locate the two exposed square pieces of metal that are on top of the fuse in question, using the positive (red) lead touch the first metal square, then do the same to the other. The voltage reading should be between 12-14 volts as shown in the image to the left. Correct readings on both sides of the fuse indicate that the fuse is not blown and working. If only one side of the fuse is giving a reading then the fuse is blown. If neither side gives a reading, current is not flowing into any side of the fuse and there is an electrical problem upward of that area on the circuit.

Note: Do not use a voltmeter that is set to Ohms to test a live electrical circuit.

Visually Checking a Fuse

Use a fuse puller to extract the fuse from the socket. (Some vehicles will have this tool inside the fuse box.) Pull on the fuse gently to remove it, you may need to wriggle it slightly but be careful not to damage it or the socket.

If you don't have a fuse puller, you can use a needle nose pliers instead.

When the fuse has been removed, check if the metal strip inside for any breaks or fractures. If the metal is strip is broken as shown in the image below, then the fuse is blown and needs to replaced. It's critically important to replace it with a fuse of the exact same amperage rating. This rating is the number that is written on top of the fuse or stated in the fuse box cover. Using a fuse of lower or greater amperage could result in a fire or damage other components of the car.

Tip: Check the for loose connections or wires around the fuse box. Tighten them and check to see if the windows work.

Damaged Window Motor

If the fuses are not blown then a deeper investigation is needed. The door panel will need to be removed. It's important to follow manufacturers procedures for removing this panel to avoid any damage. The next step is to remove the moisture barrier liner by slowly peeling it off and placing it in a safe place. Once this is done, visually inspect the plastic guides, connections, wiring and components for any sign of damage or if any of them are not secure.

Tip: Check the window switches for any dirt, loose or worn cables that could be affecting the window to malfunction.

Checking Power to the motor

Using a digital volt meter, test the connection that is going to the motor for current. Motors with two wires are analogue systems and are safe to test. However, motors with more than two wires are called digital systems and a professional diagnosis is recommended. Use the back probing method to test if power is flowing through the connector leading to the motor when the window switch is pressed (remmber to reconnect the window switch when testing). Back probe testing involves inserting the probes (leads) into the motor side of the connector as shown in the image below.

Tip: Avoid piercing any wires or front probing the connector as these could lead to further problems.

When checking the wires you are looking for a reading of either -12 volts or 12 volts. If the reading shows full current and the motor is not running it means that the motor is at fault. A lower reading means that sufficient current is not reaching the motor and that the problem is further up the circuit.

Using the drop testing voltage method you can test for any differences in volts at either side of the connector i.e. if voltage reads 10 volts at the motor side of the connector and the overall voltage is 12 volts there is resistance in the circuit that could cause the motor to run abnormally.

Tip: It's recommended to change the motor and window regulator at the same time. If one of them was to break again, you will be back to the same situation. 

Tips to Extend the Life of Window Regulators & Motors

• As soon as the window is fully up or down release the button, keeping it pressed can put tremendous strain on the motor and the components.

• Using rubber care products such as Einsett Gummi Pflege can keep rubber seals from getting hard and drying out. This will allow the window to go up and down freely. 

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