In addition, when a Mercedes-Benz power window switch fails the windows will not rise.
The main switch is located at the driver's door or center console, depending on the model.
In addition to the window not going up, you may also notice the following symptoms.
- The window won't go up but goes down
- Grinding noise from the door when you try to move the window
- Driver's window moves up very slow
- The window only moves a little then stops
- The window goes down but not up, or vice versa.
Here are some of the most common problems that prevent a Mercedes-Benz window from working properly.
1. Door Control Module DCM (N69/1)
The door control module on a Mercedes-Benz is the main unit that controls the windows and seats.
The module itself can fail and may need replacement. On some models such as S-Class, W221 the window module software may get corrupted and require an update.
If your window doesn't go up or down due to software issues, you will need to visit a Mercedes-Benz dealer and ask them to update the software versions for the door control module.
Check the fuse for the door control module as well. Typically the door control module has a 40A fuse which can blow if there is a short or a bad window or seat motor.
2. Window Switch
The window switch on the driver's door may fail. If the window switch is the problem, the power window may not move or work only in one direction.
If you don't hear the window move up or down when you press the window switch, the problem can be the switch itself.
Window switch operation can be diagnosed with a Mercedes-Benz scanner. By going to the door module and looking at the data stream, you will press the window switch and see if the door module picks it up.
3. Window Motor
The window motor on Mercedes-Benz can prevent the window from going up and down. Once the window motor fails, the window will not operate in either direction. You won't be able to raise it or lower it.
A window motor will sometimes work intermittently. If you haven't operated the windows, it may go up once, but then if you try again, the window won't go up.
Eventually, the window motor fails, and the window won't go up or down.
4. Window Regulator
If your Mercedes-Benz window won't go up and you hear grinding noise when you try to operate the window, the problem is usually the window regulator.
Some models, such as the C-Class W203 and ML-Class W163, have a small plastic on the window regulator that breaks.
The recommended method to fix this problem is to remove the door panel and replace the window regulator. Note that the window motor will need to be removed; it can be reused and doesn't have to be replaced.
5. Weak Battery
If the battery in your Mercedes-Benz is partially discharged, the window will go up very slowly then stop.
To fix this problem, start the engine or use a jump box to jump start it if necessary. Once you jump-start the car and the engine runs, the window should start going up and down without any issue.
6. Damaged Wires
The wire harness that goes from the door to the body can get damaged. You may have a broken wire inside the accordion rubber piece between the door and frame of the car.
If you open the door and the window operates properly, there is a high chance the one or more wires are cut or damaged near the door hinge.
7. Blow Fuse
On older Mercedes-Benz, you should have a fuse for the windows. The window fuse will either be in the main fuse box in the engine bay or on the side of the dashboard.
On newer Mercedes-Benz models, you will not find a use dedicated to the widows. The window motor runs via the door control module, which should have a fuse. If your Mercedes-Benz window and seats don't work, check the fuse for the door control module.
On a newer vehicle, the window circuit is protected and control by SAM and window modules.
8. Synchronization Issue
If your Mercedes-Benz window won't go up all the way but only goes up a little every time you press the window switch, the problem is easy to fix.
Press the window switch several times until the window goes all the way up. Once the window is fully closed, pull up and hold the window switch again as you would raise the window. Hold the window switch pulled for 10 seconds.
Now lower the glass to the bottom. Now the glass reaches the bottom, press down on the window switch and keep it pressed for 10 seconds.
Once you complete this procedure, your window should open and close with one touch.
If your Mercedes-Benz window is stuck down, try these temporary solutions to close the window.
If part of the window is exposed, use the palm of your hand to push the window up as you pull the window switch up. This solution works if the window regulator is faulty.
Another solution is to get outside of the vehicle and close the doors.
Point the key fob to the driver's door handle and keep the lock button pressed. You should see the windows go up and close. This works if the problem is due to a faulty window switch.
If this temporary solution doesn't work, you need to look at common problems that prevent your Mercedes-Benz from rolling up.
Faulty door module, window regulator, or motor are some of the most common problems why a Mercedes-Benz window won't go up.
The door module is a common culprit, and a software update at the dealership may fix the problem. If the door module is not the problem, you may have a faulty window regulator, window motor, or switch.
If all your Mercedes-Benz windows have stopped working, first check for a blown a fuse. If your Mercedes-Benz doesn't have fuses for the window, check fuses for the door module. Also, check the master switch in the driver's door. If the master switch is defective, it can prevent all windows from working.
Once you check these items, you need to start to look at other possible causes such as damaged wire harness, water damage, loose ground, or problems with other modules such as the Central Gateway Module.
To further troubleshoot a Mercedes-Benz window that won't go up, start by reading the fault codes from the door control module.