How to fix a stuck down window
#1
02-05-2013, 12:56 AM
How to fix a stuck down window
Started my G tonight to get home from work, and for no apparent reason the right rear window decided to drive all the way down and stay there. Not great when it's 18 degrees outside and you've got 25 miles to go. After a few hours at home, I figured out the problem and the solution. Some notes if this happens to you:
(I have a G35S with nav, premium package, etc. - not sure if this works for all Gs, so use at your own risk. I also recommend reading the BCM section of the repair manual if you have any doubts).
1. You have to stop current from going to the window motor before it burns itself up. Your options: 1A. If its not the driver window, press the window lock-out switch on the driver door switch panel (the switch that prevents any of the passengers from using their windows). You should here the relay in the door of the affected window click off. Or, 1B, yank out the related fuse. Again, you should here the relay click off. The window motors are DC, and when they aren't turning they draw maximum current. They will get hot and melt the insulation on the windings pretty fast. I'm guessing you have a minute or two.
2. The way the switches are designed, it's pretty easy for water to get down into the circuit board. It's difficult to tell if it's the driver door switch sending a signal to the affected window switch, or the window switch itself. In my case, the right rear window was going down, but the root cause was the driver door switch. You've got two choices: 2A. By new or used replacement switches. Not cheap. About $130 for a rear switch and $235 for the drivers door online (new). Cheaper used. Or, 2B, disassemble the existing switches and clean them. This worked for me. The plastic bessel the switches sit it pops vertically out of the door. Some plastic automotive pry bars makes this a lot easier. Once you have the bessel out, squeeze the release tabs on the cables, disconnect them, and take the switch and the bessel inside (or at least some place warm). Using the plastic pry bars, carefully pull the switches out of the bessel (4 tabs per switch), and using the pry bars yet again disassemble the switch (6 tabs per switch). Each switch consists of a top cover with the mechanics, a membrane, a printed circuit board, and a bottom cover. Note the small black box on the printed circuit board is the relay you heard clicking before. Using a lint-free cloth with a little alcohol, gently clean the printed circuit board, the membrane cover and the top and bottom cover. Get a can of blast away and blow all parts clean and dry before reassembling.
3. If this doesn't work, and you end up ordering new or used switches, there is a trick to getting one of the rear windows back up. Believe it or not, the pin outs on the rear switches are the same. The commands from the driver door switch are sent over a serial bus to the other switches. Each switch has a serial ID. So if for instance the right-rear window is stuck down, you can unplug the right-rear switch and plug the left-rear switch it its place. To get the window up, pull the LEFT-rear switch on the drivers door. I know, this seems strange, but the driver switch is sending a signal via serial link to the left-rear switch, and because the left-rear switch is plugged into the right-rear window, the right-rear window will go up. Put the left-rear switch back where it belongs (in the left-rear door) and leave the right-rear switch unpluged until you get a new / used one. This should allow you to put power back without burning up the window motor, and drive around with the windows up.
I'm not sure if the trick in #3 works for the front passenger door, but my guess is it would. I'd check the wiring diagram first to make sure the pin outs are the same. The section you need is called BCM (Body Control Module) and the schematics and pin outs are on pages PWC-74 to 78.
Hope this helps. Sorry I didn't take pictures. Good luck.
(I have a G35S with nav, premium package, etc. - not sure if this works for all Gs, so use at your own risk. I also recommend reading the BCM section of the repair manual if you have any doubts).
1. You have to stop current from going to the window motor before it burns itself up. Your options: 1A. If its not the driver window, press the window lock-out switch on the driver door switch panel (the switch that prevents any of the passengers from using their windows). You should here the relay in the door of the affected window click off. Or, 1B, yank out the related fuse. Again, you should here the relay click off. The window motors are DC, and when they aren't turning they draw maximum current. They will get hot and melt the insulation on the windings pretty fast. I'm guessing you have a minute or two.
2. The way the switches are designed, it's pretty easy for water to get down into the circuit board. It's difficult to tell if it's the driver door switch sending a signal to the affected window switch, or the window switch itself. In my case, the right rear window was going down, but the root cause was the driver door switch. You've got two choices: 2A. By new or used replacement switches. Not cheap. About $130 for a rear switch and $235 for the drivers door online (new). Cheaper used. Or, 2B, disassemble the existing switches and clean them. This worked for me. The plastic bessel the switches sit it pops vertically out of the door. Some plastic automotive pry bars makes this a lot easier. Once you have the bessel out, squeeze the release tabs on the cables, disconnect them, and take the switch and the bessel inside (or at least some place warm). Using the plastic pry bars, carefully pull the switches out of the bessel (4 tabs per switch), and using the pry bars yet again disassemble the switch (6 tabs per switch). Each switch consists of a top cover with the mechanics, a membrane, a printed circuit board, and a bottom cover. Note the small black box on the printed circuit board is the relay you heard clicking before. Using a lint-free cloth with a little alcohol, gently clean the printed circuit board, the membrane cover and the top and bottom cover. Get a can of blast away and blow all parts clean and dry before reassembling.
3. If this doesn't work, and you end up ordering new or used switches, there is a trick to getting one of the rear windows back up. Believe it or not, the pin outs on the rear switches are the same. The commands from the driver door switch are sent over a serial bus to the other switches. Each switch has a serial ID. So if for instance the right-rear window is stuck down, you can unplug the right-rear switch and plug the left-rear switch it its place. To get the window up, pull the LEFT-rear switch on the drivers door. I know, this seems strange, but the driver switch is sending a signal via serial link to the left-rear switch, and because the left-rear switch is plugged into the right-rear window, the right-rear window will go up. Put the left-rear switch back where it belongs (in the left-rear door) and leave the right-rear switch unpluged until you get a new / used one. This should allow you to put power back without burning up the window motor, and drive around with the windows up.
I'm not sure if the trick in #3 works for the front passenger door, but my guess is it would. I'd check the wiring diagram first to make sure the pin outs are the same. The section you need is called BCM (Body Control Module) and the schematics and pin outs are on pages PWC-74 to 78.
Hope this helps. Sorry I didn't take pictures. Good luck.
#3
02-05-2013, 01:58 PM
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