The window regulator is the mechanism that actually moves the window up or down, with either a window crank or power window motor. Before assuming your regulator is bad on any car including the BMW 325i, check the fuse box, then check the window switch. If all else fails, the regulator or motor may be the culprit. Replacing these is no fun task to do but it can save you some money on labor by doing it yourself.
What You Need
- Phillips Head screwdriver
- Panel removal tool (butter knife)
- Punch + Hammer
- Drill + bits
- New regulator and/or motor
- Rivet gun + Rivets (Optional but preferred for an OE quality installation)
- T30 Torx
- Window regulator clips
After testing the circuits and assuring that it is in fact a motor or regulator it is time to pull the door panel off. Remove the screws that attach the panel to the door, there are two just below the door handle. Remove the door panel using the interior tool to “pop” the clips, without breaking them or causing them to separate from the door panel itself. After the door panel is removed you will need to carefully remove the plastic sheeting that protects the door's internals from moisture.
Next, with the panel and the plastic removed you should now be able to see the inner workings of the door, and if you were having any other issues; handle, door lock, or speaker, you can replace what is necessary. For my car when I had this issue my window was stuck in the full up/closed position. Once the door panel was off I turned the key to position 2 and tested the switch to listen for any kind of noise, the motor was making a clicking noise as if it was trying to move but was jammed. This told me that the motor was more than likely good and I needed a regulator as no movement was taking place.
Regulator Removal
If possible, roll the window down to where you can see both of the regulator arms where they connect to the window. If you cannot move the window electrically, just tape or secure the window so it does not fall as you start to remove the components. Unplug the motor from the harness and remove wires that are in the way. With a hammer and punch, carefully punch out the center pins of the rivets holding the regulator to the door. After you have done that, grab the drill and drill bit just larger than the open hole where the pin was, and drill out the rivets.
There is one Torx screw holding the regulator to the door that will need to be removed. To prevent the glass from falling into the door, “pop” the arms from the plastic, and pull the regulator and motor from the door.
If you are replacing the whole assembly the next step is not necessary
Flip the assembly over so that the side facing the inside of the door is up. Remove the three T30 torx screws holding the motor to the regulator. If replacing just the motor, plug in and test the new motor works and put it to about halfway through its cycle. (The regulator has 46 teeth and the motor had 10 teeth on the gear and would cycle 20 times, putting it in the middle will give it more than enough room to roll the window up and down) If replacing just the regulator first make sure you grease every part that will be moving and install the motor in the same fashion as replacing just the motor.
While everything is out, it is a good idea to make sure everything is greased and clean out the inside of the door from what might have fallen in, if your glass has ever been broken, there could be shards left that rattle around. Also, grease the tracks the window slides in - it will make the whole operation smoother and easier on the motor. Grease the regulator as well as any and all moving parts or tracks for moving parts.
It is highly recommended to replace the plastic pin clips that hold the glass to the regulator. This is another part where it could get pretty tricky, the best thing to do is to get the assembly back into the door and riveted in and bolted in place, then connect the motor and get the arms so they are visible and then you will want to lower the window by hand until you can “pop” the arms into the new clips on the glass. It is tough to get leverage to get them fastened, just be careful, you do not want to break the glass. But, once everything is clipped and riveted, test the operation of the window. If it rolls all the way up and down put the door back together and bask in the glory of saving money by replacing your own window regulator. Which if I am not mistaken, the time a shop would charge is about 3.5hrs, at a dealer that is usually about $350-$400.
