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Are you tired of having to open your door and get out at the drive-through restaurant to retrieve your burger? Does your window constantly reverse itself when you’re trying to raise it? Perhaps it’s time to replace or clean your window regulator, or install a new power window motor. The difficulty of this project varies depending upon which year car you have, but the results are immediate and quite rewarding. Not much is better than driving in your BMW with the sunroof open and the windows down on a nice, sunny day. Having a broken window regulator can surely put a damper on that. Or worse—if you own a convertible, a broken window regulator will keep you from putting the top down.
The first step in replacing either the regulator or the power window motor is to remove the door panel. Make sure you eliminate the power window switch as a potential problem, however, before you start tearing into your door. Double-check all the fuses that control the power windows, and swap out the relays to make sure there isn’t a problem with one of them. If one window works and the other doesn’t, chances are it’s the window motor or the window switch. The switches themselves are often faulty, which can sometimes make this an easy fix. Test the switch by removing it from the center console, and swap it with one that is working. If there is any noise coming from the door (such as clicks or whines) but the window isn’t moving, then it’s quite obvious the motor is fine, but the regulator needs to be repaired.
For details on removing the door panel, see Project 67. When you have the door panel removed, you can access the regulator. With your fingers clearly out of the way, roll down the window until it’s about 75 percent of the way down. Take a look at the white, square plastic sliders that attach the bottom of the regulator to the window. If they are worn (and they’re almost always worn), replace them using the procedure documented in Photo 3.
If your window doesn’t respond at all and you’ve eliminated the possibility that it might be a broken window switch, then you’ll need to remove the window regulator. Unfortunately, the window regulator is attached to the door frame with rivets. You will need to drill out these rivets in order to remove the regulator from the door. (See Photos 2 and 3 for details on removing the regulator.)
With the regulator detached from the door frame and the window, you should test the motor prior to disconnecting the electrical connection. With your hands out of the way of the regulator, carefully press lightly on the window switch and see if the regulator moves. If the window was stuck previously, but now it moves, it means that the tracks of the regulator and the window are sticky and need lubrication. Photo 4 and Photo 5 show the process for greasing the regulator tracks prior to reinstallation. If the motor doesn’t move at all, it is probably worn out (assuming you’ve checked the window switch).
Before you reinstall the regulator, I recommend you inspect and replace the front window channel guide too, if it’s worn. This is the channel that guides the front of the window as it is raised and lowered by the regulator. Also worth replacing are the window slot seals. These inner and outer window scrapers keep water from dripping down into the recesses of the door. You should grease each and every moving part of the regulator: the slides, the motor, the gears, and the large-toothed section of the regulator.
Before you close everything up inside your door, it’s a wise idea to test the proper operation of the window. Hook up the power connections to the window motor, and try to raise and lower the window. Also verify the stop positions of the window once you have reinstalled the regulator. There are screws located inside the door that control these stop positions. Once you’re satisfied everything is running smoothly, reseal the door panels and you’re on your way again.
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