2008 BMW 135i Window Regulator Replacement Cost

If one of the windows in a vehicle will not open or close properly, a failing door window regulator might be the cause. A window that is moving intermittently, or one that gets stuck on the way up or down, could also indicate a broken regulator. Other symptoms might include a clicking, chattering, or grinding noise when the window moves. In some cases a severely damaged window regulator could cause the window to drop inside the door.

A vehicle with a failed window regulator can be driven if weather conditions permit, but the window may be stuck open. If the window is loose it should be made stationary until the regulator can be replaced. Hold the window in place with tape for a temporary solution. Care should be exercised with a window that has come loose from the regulator to prevent the glass from breaking inside the door.

Window regulators are not a consumable item, but they do wear out. It is not uncommon to replace a regulator in a car with 100,000 miles.There is however no recommended frequency of replacement.

A failing window regulator is diagnosed by actuating the window motor switch (or window crank in the case of a manual regulator) and observing if a) the window regulator motor is working; b) the window is travelling smoothly in its tracks; c) the window is travelling fully from top to bottom; d) the window is tight or loose in its opening. If the regulator motor is not working, a technician might first check for a blown fuse or faulty window switch. But if the regulator motor is working and the window is not moving smoothly, or it is not travelling all the way up or down, or it is loose in the opening, a technician will remove the interior door trim panel to look inside the door and verify that the regulator is broken.

Replacement of a window regulator depends on the type of vehicle and style of regulator. In general, a technician will remove the interior door trim panel, taking care not to damage the latch cable or any electrical wiring that is attached. Next, the door vapor barrier is removed. The window is disconnected from the regulator (this may be difficult if the regulator is not working at all) and removed from the door. Finally, the regulator is removed from the door and (in the case of a power regulator) the regulator motor is removed from the old regulator and installed on the new one before reassembly.

Door window regulators can fail but the door window motor may continue to operate as expected. In this case, if the motor tests okay and is available separately, only the regulator needs to be replaced.

RepairPal recommends that a repair manual be referenced before removing an interior door trim panel to prevent damage to the retaining clips, electrical wiring, and latch cable. Also, if a power window regulator is broken but the regulator motor is still operational, it may be possible to transfer the motor to the new regulator (this is not possible on some vehicles as the motor and regulator are integrated).