There is nothing like a well-functioning window. It allows us to enjoy a beautiful spring breeze, order fast-food, and a functioning window can be a saving grace on a hot summer’s day when the a/c system has broken. But what happens when something goes wrong? One day the window switch won’t work or you begin to hear strange sounds emanating from the door panel when the window moves.
My brother drove for two months in the blistering North Carolina summer weather while his window was hopelessly stuck with an inch gap from the top of the door frame. He finally ordered the part and I finally fixed it, but not until after he had endured countless days of 90 degree weather and rain water trickling into the car.
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BMW E36s have a reliable reputation compared to many other 3 Series BMWs, but failed windows are an extremely common issue on high mileage E36s. There are a number of problems that can cause your window to become inoperable. This article will breakdown the different symptoms and instructions on various repairs to get your window back in working order!
First Things First
I know your eager to drop a couple hundred bucks and several hours of your time to remove the door panel and replace the window motor and regulator but before you do that lets discuss the easier repairs that could be causing your window to fail. Typically, BMW E36 maintenance is not very difficult, but window regulator repair is one of the exceptions in my mind so if you can get away with an easier repair it will save you a significant amount of time.
Window Switch
Spill your morning coffee on your center console switches lately? In my experience the window switches are rarely the problem, unfortunately the far more frequent issue is the window motor however it is certainly worthwhile to check. This is usually the first thing I check on a non-operating window. Simply swap the non-operating window switch with a working window switch. If the window starts working you have identified your problem and it’s only costed you a couple bucks and a few minutes of your time! The switches are easily removed with a flathead or a tack puller.
Plastic Sliders
The plastic sliders are one of the most common causes of a non-working window. The window has two metal rails attached to the base. The regulator is attached to the window through two plastic “sliders” which glide along the rails. Over the years these plastic sliders become brittle and break apart. This can and will cause the regulator to break away from the window.
Identifying this problem is simple, but it does require that you remove the door panel. Once the door panel is removed look at both of the metal rails at the bottom of the window. If the regulator is not attached you will need to order two new plastic guides (preferably more as they are a common fail point and cost only a few bucks). The regulator joints are locked into the plastic glides through a metal clip which must be inserted after pressing the joint into the glide. It’s a real pain in the A$$ to get both of them pressed in.
Once you’ve got the new glides in, make sure to spray the rails with lithium/silicone grease. Keeping the moving parts well-greased helps to ensure the longevity of the regulator and motor!
Window Misaligned
This is often a symptom of an additional problem with the window. When the regulator breaks out of one of the plastic sliders it can cause the window to misalign. This is simple to spot without removing the door panel. You will notice that the window rises or lowers at an odd angle. Be careful not to try and operate the window in this condition as I’ve seen someone bend a perfectly good regulator by stubbornly using the misaligned window.
Motor Failure
Window motors are a common problem on E36s. They typically don’t pull a “fuel pump” type failure and die all of a sudden. Instead, you’ll likely notice that the window works intermittently for a month or two and progressively gets worse until it passes from this world.
In order to test the window motor first you need to remove the door panel and remove the foam insulation inside to access the regulator and motor. I have a video on the door panel removal process here. Try not to tear the insulation, as you would be amazed how much BMW charges for it.
Once the door panel is removed there are two ways to test it. If you have a volt-meter, pull the power cable from the motor. If its getting current when the switch is held down but the motor does nothing you likely have a bad motor.
Second option is to tap the metal portion of the motor with a mallet. If the motor now works than you have a bad motor. Don’t believe for a second that you have fixed the motor by tapping it with a mallet. The motor might work okay for a while afterwards, but it will fail again soon. It’s best to go ahead and replace it.
Tools Needed
Safety Glasses
T30 bit or socket & ratchet
5 mm allen socket & ratchet
Lithium Grease
Dremel Tool/Nail Set/Drill
Lots of Patience & an Assistant
Replacement
Position the window completely up. If your motor has completely failed, try and give it a whack with a mallet to get it to come back to temporary life. If not, this job will be a little more difficult, but not impossible!
Unfortunately, in all of BMW’s wisdom they decided to use rivets to hold the regulator to the door frame. This really sucks as these rivets must be removed in order to remove the motor. I drill out the rivets, but I warn you BMW used a really hard material for these rivets and it takes longer than expected to drill them out. Alternatively, you can also use a nail set to punch out the center of the rivets.
If your only replacing the motor than you do not have to remove the regulator. Although, I recommend to replace them together you can replace just the motor. There are three T30 torx screws holding the motor onto the regulator. Unfortunately they are behind the regulator and take a lot of patience to remove. The regulator assembly can be pulled about 2 inches away from the door frame. Take care not to pull anymore than this as you may bend the regulator.
Grab a helping hand to hold the window in place while you remove the window motor. The motor holds the regulator in place, and the shock of removing it can cause the window to crash down at the bottom of the door.
At this point installation is the reverse of removal, check for the black plastic bushing on the motor gear. It may have came out with the old motor or stayed in place on the regulator.
Regulator
After removing the door panel you will notice that the regulator is actually made of pretty thick metal. This part does not go out frequently however the pivot bar sometimes bends overtime. At that point the regulator must be replaced.
Replacement is the same as replacement of the motor with some additional steps. After drilling out the rivets you will need to remove the allen head bolt holding the pivot bar to the door frame. The bolt has a 5 mm head.
The Regulator is attached to the window through two plastic glides and held on by a clip. The clips must be removed to pop the glides out. Its helpful to have a helping hand at this point because there is nothing to hold the window in place once the regulator has been removed.
Once the Regulator is removed, remove the 3 T30 screws holding on the window motor, and remove the motor.
If there were rivets holding the regulator in place you will likely want to replace them with bolts. Re-insert the regulator back into place and insert the four bolts. You can optionally use blue loctite to help secure these bolts for the long-term.
You will need to push the window down EVENLY so that the bottom rails are visible, and move the regulator to align with the window’s bottom rails. When you snap the new regulator into the plastic glides you should hear a loud clicking noise. Once you hear the noise you can lock the regulator in place with the clips.
Preventive Maintenance
Whenever I open up a door panel to change parts related to the window I spray lithium/silicone grease like a madman. All of the movable parts you see and the railings should receive a coat of grease. This will help increase the life of your window parts and decrease the likelihood of you having to go back into your door anytime soon.
Check out this video on BMW Power Window Diagnosis!
Conclusion
Hope this article helped with any issue your window might be having. Although BMW windows can be a real pain, once you’ve done it once the process gets significantly easier the second time!