bombay digital > boxster > projects > power window motor repair

{ power window motor repair }

This how-to describes the process of repairing and replacing a broken power window motor or broken door glass on a Boxster. The process is presumably very similar for a 996 or other recent model Porsche.

You can click any small photo shown here to see a larger version of it.

Disclaimer: Use at your own risk. Not my fault if your engine falls out, you lose a finger, or you get an airbag in the face.

Tools

You'll need the following tools to make the repair.

Caveat!

The exact type of fasteners you encounter may be different, or may even be missing! For example, where I describe a Philips head screw you may find a T25 torx, and so on. This is not the least because if a mechanic has ever worked on this part of your car before, they may have put things back differently or grabbed the wrong screw, etc. After first writing this article in 2004, I later removed the door panel for other reasons in 2010 and found a different fastener in one place, and no fastener at all in two others. Someone has been in there, and I don't remember what for!

Parts

Depending on what is broken, you will of course need the replacement parts. The window is a single unadorned piece of safety glass. It is operated by two parts: the "regulator" or "lifter" system that slides the window up and down; and the small electric motor that drives the regulator. The Porsche dealer should be able to sell you a window regulator for about $270, and if the window motor is OK, then the regulator is all you really need. At the recycling (junkyard) place where I purchased my replacement parts used, they only sold the motor and regulator as a single unit, and it was $200 total. If you're just replacing broken window glass, you should not need anything other than the single piece of window glass.

Part Driver's Side (left) Passenger's Side (right)
electric motor 986.624.101.xx 986.624.102.xx
window lifter (regulator) 996.542.075.xx 996.542.076.xx
door glass 986.542.511.xx 986.542.512.xx

(In Porsche part numbers, the last two digits are a revision number, which increase over time as Porsche makes minor changes to the part. I denote the revision number here with "xx".)

You have several options for obtaining these parts. From the dealer, a motor and regulator together will run you over $500. If you do a web search for alternate parts sources, you may find them for a little bit less. My experience in having the dealer diagnose the problem was that after a $147 charge for diagnosing the problem, the dealer said I needed a motor and regulator (as I recall, the estimate was $515 parts and $450 labor). It was the nearly $1000 estimate that led me to research doing the repair myself. However, when I did it myself I discovered that there was nothing wrong with the motor—only the regulator needed replacing. In retrospect, the dealer in Oakland did nothing to diagnose the problem other than to press the power window button and verify that the window did not operate, and then just slapped me with an hour and a half of "labor" charge, and an excessive part cost estimate. I know now they didn't even remove the door panel to really see what was wrong (the foam liner adhesive bead was untouched from the factory), and I suspect that had they performed the repair they would have replaced the perfectly good motor. For an hour's labor they could have determined that the motor was OK.

In addition to saving more than $400 in labor by doing the repair yourself, I recommend getting a motor and/or regulator from a "recycling" or "salvage" place. Also known as a junk yard. I got a perfectly good used motor and regulator for $200 from Silver Star Recycling in Rancho Cordova outside Sacramento. (They would not sell me just the regulator alone after I discovered that my old motor was OK, presumably because when they come off a junk car they are attached together. New parts should be obtainable separately.)

So, bottom line, instead of a dealer repair at nearly $1000, it cost me just $200 in parts plus my own labor. It took me quite a while to do it since I had to learn it, but I think that using these instructions you can probably do it in 3 hours.

Overview

The basic outline of the procedure is as follows. I'll assume you're not just replacing the glass; if that's all you're doing, some of these steps are of course not necessary (namely, you wouldn't have to r&r the motor+regulator).

Door Panel Removal

The first step is to remove the interior door panel. This procedure has already been nicely documented by Jason Reiser. (NOTE: That link has gone dead. Good thing I put notes here.) I found a couple of things different on my car from Jason's instructions, so I'll just recap the steps with a few comments. You will find his instructions and pictures a bit more detailed.

1. Disconnect the battery as a precaution while working near the side impact airbag. A 10mm wrench will loosen the negative terminal cable so that you can remove it.

2. Pry off the plastic trim piece surrounding the door lever, by prying from the bottom. If you look closely there's a little slot on the bottom edge where you can put a flathead screwdriver. But try pulling with your bare hands first. Avoid pulling hard on the end with the pointed tip; that's where the only real attachment hook is, and it's the only thing that could break off.

3. Remove the T30 screw that you have now exposed next to the door lever.

4. Pull off the C-shaped piece of plastic located at the midpoint of the door grab handle. Note that it is labeled for which side of the car and with an arrow pointing up. This exposes a 3" long T30 bolt that you need to remove next.

5. Pulling slightly on the door lever, you'll see a screw behind it. On Jason's car it was a Philips head screw. On mine it was another T30 bolt, 2" in length. Remove it.

6. At this point you can remove the door grab handle by sliding it forward and up. You may as well do this now, because there's nothing holding it on and you wouldn't want to accidentally grab it and rip it off.

7. Inside the door pocket is a plastic Philips head attachment screw to remove next. I found it difficult not to strip the soft plastic of the screw head. Using a door panel tool or other similar thin prying tool, you'll have to pull on it from behind while unscrewing it. Or, you can actually just pop it if necessary out with a fair amount of force, jumping the threads, harmlessly.

8. Pry off the little plastic "AIRBAG" logo plug on the airbag panel. It's just held on by friction fit on all four edges. It's hard to get something under it to pry with, without marring the plastic or the surrounding leather, but that's the only damage you can do even if you pry too hard. One suggestion has been to wrap something like fishing line around it to pull with. Removing the plug reveals a 4mm hex driver screw to remove next.

9. Remove the triangle-shaped trim piece that houses the side mirror adjustment switch (driver side) or electrical wires (passenger side). Simply pry from the bottom until it starts to pop loose. Then slide it up. Jason's photos show you how it's actually attached.

10. Now the only thing left to do is to pry the entire door panel off the door, so that each of the door clips pops away. The following picture shows you where each door clip is, so that you can pry at the correct location. All but one of the clips is a white plastic plug. The one at the upper edge of the front of the door is black and not easy to see in the photo, so I've added an arrow to show where it is. If you start at one end and work your way around, you can just pry the first one or two, and then continue by pulling the panel at each clip with your hands, sliding your fingers between the door panel and the door as you go.

11. Once all the door clips have been popped out, the door panel is simply hanging on the window ledge. Lift it up. There are a couple of wires attached, and you'll probably want to disconnect a couple of them so you can move it out of the way. The footwell light wire just slides out of its housing with the bulb. The other electrical connector is a little plug by the door lever cable.

12. The only other cable tethering the panel to the door is the door lever cable. The first time I removed the door panel, this cable was zip-tied to its connector and I didn't want or need to cut the tie, so I just left the door panel standing on end, tethered and leaning against the open door edge while I worked on the window. More recently I removed the door panel and the zip tie was gone, and I really did want to completely set the panel aside, so that was good. The zip tie is evidently not completely necessary. You can disconnect the door lever cable from the lever mechanism easily: the solid wire end of the cable is just an L-shaped hook that goes into a hole in the lever; before the L bends it is restrained with a little black piece of plastic, and if you snap the wire out of the restraint it slides right out of the hole. You do not need to touch the black plastic collar that actually goes into the hole, only the end where cable feeds in and is restrained. Once you detach the door pull cable, the door panel is completely free.

Accessing the Inside of the Door

So now you have the door panel off the door, perhaps still tethered by the door pull cable unless you unhooked it. There are just a couple more steps to get into the interior of the door where the window mechanism is. Note that if you are just removing the door glass, and the window is up or operable, you don't need to do this. This is only necessary to get at the motor and regulator, or to get at the window clamps when the window is in the down position.

1. Unplug the door speaker cable.

2. Remove the door speaker via the four T15 screws at the corners of the speaker box. The speaker box now lifts up and out of the door. Push the end of the speaker cable through the foam liner and into the door.

3. Now you just need to pull back the foam liner. It's simply stuck to the door with a bead of adhesive along the outer edge. You don't need to pull back the section towards the back of the car or along the top. Start at the front of the airbag box and work your way forward, then down the front of the door, and along the bottom, until you've exposed the large opening as well as the three 10mm nuts that hold the motor in place. You'll probably want to use some tape or some kind of clip to hold the foam back and out the way while you work.

Removing the Window Glass

The window glass is attached to the regulator with a clamp at each end of the bottom edge.

Each clamp is part of the window regulator unit. A T30 bolt tightens the clamp around the window to secure it. You should either mark the glass with a pen, or make a mental note of where the glass sits in the clamps. The corner of the glass where its forward edge meets its bottom edge is exactly at the forward edge of the forward clamp. When you put the glass back in place, you need to remember this positioning.

If the window is in the up position, you can remove the glass by accessing the clamps through two holes below the window sill. Take a look at the marks on the photo further down the page. At the top of the door are two nuts that secure the top of each regulator track rail; these are circled in green in my photo. Just below each nut is a hole in the door that is covered with a black plastic/foam plug. These holes line up perfectly with the location of the glass clamp when the window is in the up position. It's a bit easier to access the clamps this way than when the window is in the down position.

To remove the window glass, loosen the T30 bolt on each clamp until it's loose enough that you can push the window glass upward. Don't remove the bolt completely. If the window is in the down position, the rearward bolt may be difficult because there is very little room between the bolt head and the door frame in which to fit a driver. When my regulator was broken and the window was stuck in the down position, I was able to turn the rear clamp bolt a little bit with a regular T30 screwdriver at an angle, but then had to resort to inserting just a T30 bit and turning the bit with a box wrench inserted sideways into the little space. Even the bit barely had room to fit. It seems like there's got to be a better way to access this bolt, but perhaps some kind of T30 ratchet with a very short bit is the correct tool. A reader Louis emailed me to report that an L-shaped T30 provided for assembly of some Ikea furniture worked well for this.

With both clamps loosened, you can slide the glass out. If it's in the up position, just pull up from the top; you may have to pull the rear edge up first and then ease the front out at an angle. If it's in the down position, from the inside of the door push up on the bottom edge of the window glass, just as the motor would normally do, and it will slide upward and out through the top of the door.

Here's what the glass piece looks like by itself.

Removing the Regulator and Motor

The regulator and motor are attached together and must be removed and replaced together, although once they are removed, they can be separated and you can replace one or the other, put them back together, and reinstall.

This photo shows what the regulator and motor look like, sitting on the ground. This particular unit is in the "up" position, so you'll notice that the window glass clamps are at the top of each track.

The system runs the cable in a figure-eight loop. So when the motor turns counter-clockwise in this photo, it moves the cable up and to the right as it moves through the regulator's spool housing, and both clamps move downward in their tracks and pull the window down...

...and when the motor turns clockwise in this photo, it moves the cable to down and to the left as it moves through the regulator's spool housing, and both clamps move upward in their tracks and push the window up.

Here is the exposed door panel with the regulator and motor attachment nut positions highlighted. These are 10mm nuts that screw onto threaded pins that are part of the motor and regulator housings. You can see the notations more clearly in the large version (click).

First, disconnect the motor from the wiring harness. The connector is just visible in the door opening below the motor. In the photo the red arrow points to it.

Next, remove the three motor attachment nuts, circled in blue. The motor is now free, but is held in position by the tension of all the cabling of the regulator. Leave the motor in position for the moment.

Now remove the two bottom regulator attachment nuts. These are accessible from the bottom outside face of the door. Each is covered by a little plastic/foam plug. In the photo, the yellow arrows point to these. Remove the plugs and remove the nuts. However, I would recommend that before you remove them, you mark the location of the edges of the regulator tracks where they sit on the bottom inside floor of the door. There is a quarter-inch or so of adjustment play for the mounting position from left to right relative to the car (this affects slightly the angle of the window as it leans in towards the roof line), and it's probably best to put them back where they started. I didn't realize this when I did it, so I tried my best to put them back in the middle of the adjustment range, and it was fine.

Finally, remove the two top regulator attachment nuts. In the photo, these are circled in green.

One more thing: on my car the regulator cable was zip-tied to the door at the location marked with the green arrow. I cut the tie to free the cable.

Now the motor and regulator can be carefully pulled out of the door through the large opening. You'll have to experiment with how to best angle them out, but since the cabling is flexible, you can lean the regulator tracks to make it work.

OK, you're all done with the "remove"!

Details of Motor and Regulator

Here are a few more details about the motor and regulator.

First, a warning. Do not operate the motor+regulator system unless it's under full cable tension! You might think to test the operation by running the motor with the regulator cabling separated from the runner tracks if it's not working right and you are having trouble getting the cabling routed through the tracks and pulleys. The problem is that when the motor winds the cable spool without tension, cable is pulled onto the spool, but not pulled off the spool, and this seems to lead to the cable getting mangled and tangled inside the the spool housing, which basically ruins the regulator as a unit. What makes it all work is that the consistent tension on the cable loop means that as the spool pulls cable in from one side, it's also effectively pulling cable out of the other side, and it's true regardless of which direction the reel is turning. Without the tension, it can only push the cable out, and what happens is the cable doesn't push much and bunches up inside the housing and gets tangled and jammed.

You can, however, separate the motor from the regulator, plug it in, and see if it works. In my case, the motor was fine and the regulator cabling had gotten mangled inside the cable spool housing. So I had the option of just buying a new regulator and keeping the old motor.

Once again, here's the passenger side motor and regulator, lying on the ground, in the same orientation as in the door photos above, looking at it from inside the car. The window glass clamps are at the top—the window is "up".

If we flip the system around, we can see it as if looking from outside the car. Here you can see the four pulleys that the cable rides around. If you look closely, you may be able to make out a little nub that is crimped onto the cable for each glass clamp. The clamp slides up and down in the track, pulled by the nub. Apparently, the motor senses the extra tension when the the clamp "hits" either end of the track, and stops.

To separate the motor from the regulator, simply remove the three bolts that are used to bolt the motor to the door. Use a wrench to undo them, and pull them all the way out. You can then pull or gently pry the motor away from the regulator by putting a screwdriver between them through the large gap where you see the motor gear. By prying or pulling, you're simply disengaging the motor's drive gear from the cable spool's gear teeth. Here are the two pieces separated. That's the motor above, and the regulator's cable spool housing below.

(Please ignore the fact that the cables coming out of the spool housing are detached, etc. This is my old damaged regulator with the broken connector and mangled cable hanging out.)

You can even open up the regulator's cable spool housing to see if the cabling has gotten mangled, although you need to be careful that you don't mess up the cable spool winding—it's very difficult if not practically impossible to re-spool the cabling correctly if you pop the green spool wheel out. Seriously, if the regulator is OK and spool is not tangled, don't remove the spool as an educational experience or you may find yourself in need of a new regulator. To look at the cable spool without removing it, simply remove the single T25 screw that holds the metal cover on.

The cable and the vertical cable guide tracks on the regulator should have a modest amount of clean, golden yellow grease to lubricate everything. On my dead regulator it had all turned to a gritty, grimy, gray paste. I presume this was due to accumulated dust and dirt. I could hear the grinding and scraping noises, before it stopped working and something broke. Here are several photos of my jammed cable spool in various stages of disassembly and untangling. Unfortunately, once kinked, the cable will never straighten out. The green spool pops out of the housing if you just push firmly on it from behind.

Look at all that dirt and grime in the grease. You can see some original clean, clear, yellow grease in the spokes of the spool and another dab towards the top of the housing, both places where it wasn't being used and abused. No wonder something eventually ground to a halt.

Re-Installing the Motor and Regulator

Once you have the new motor and/or regulator ready, you simply reverse the procedure.

First, wrangle the whole unit into the opening in the door frame and place the four corner points, and the motor mounting bolts, in position.

Attach and tighten the mounting nuts for the motor.

Using the reference marks you made earlier (if you made them), position the bottom attachment points of the tracks and attach the 10mm nuts in the underside of the door. Attach the upper mounting nuts for the tracks. When all four corners look good, tighten them and replace the rubber/foam seals on the bottom of the door.

(You might want to connect power to the motor at this point and test the mechanical operation before putting the glass back in place.)

Slide the window glass down through the slot in the door.

And guide it into the clamps of the regulator.

Before tightening the glass clamp bolts, make sure the window is positioned correctly in the fore-aft direction. I suggested earlier that you either mark the glass with pen to align the forward bottom corner of the glass with the forward edge of the front clamp.

Finally, tighten the clamp's main bolt enough to hold the glass...but of course not so much as to crack it! It does not seem that it needs to be extremely tight, because gravity does a lot of the work.

The shop manual says that you can adjust the left-right tilt of the window, and therefore the amount of pressure the glass puts on the rubber weatherstripping along the roof line, by adjusting the strange bolt that runs vertically in the glass clamp. I actually can't see what effect that bolt would have on anything! The adjustment play in the bottom mount points of the regulator's tracks would seem to be able to affect this, perhaps in a more coarse-grained way. It all seemed to be aligned correctly to me after I put it back together, without having to adjust or fine-tune anything.

Plug the motor back into the wiring harness and give it a test. (Reconnect the battery while testing.) If all is well, you now just need to button everything back together.

Re-Installing the Door Panel

From here, you are simply reversing the door panel procedure.

Put the foam liner back in place, held by the existing bead of adhesive. Pull the speaker cable plug through the little slit.

Put the speaker box back in place, and plug it in.

Put the door panel back in place, first lowering it onto the top ledge, then pressing the door panel on at the location of each clip. You should hear each clip snap back into its hole.

Re-attach the various screws and trim pieces in reverse order.

Reconnect the battery. Enter your anti-theft radio security code.

Woo-hoo! Have a beer!