Power window suddenly not working

325i/1993 · 325i/1993's Garage

I need some help here regarding my power window which stop working all of a sudden. I really has no clue whats been goin on with this car. I'm just worried because one window at the back is half open and for the past 2 days now were having some thunderstorm late at night, I just put some black plastic garbage bag to prevent the rain from soaking the interior. This is a 1993 325i 4 dr. I really appreciate any advice...thanks.

Manolito · 08-12-2009, 08:02 PM

Most likely is a failed regulator, which is the mechanism that holds the window straight and level and moves it up and down when the motor turns. I have never pulled off a rear door panel, but I doubt that it is very difficult. There should be instructions on the web.

I just looked at one - start by pulling outward and forward (toward the hinges) on the ring around the door latch handle. It will be very tight, but it will unhook and pop off. Then unscrew the plastic lock knob on top. Then remove the screws that are beneath the plastic caps under the door handle. Then carefully unsnap the snaps around the perimeter of the door panel using a large flat tool. Then carefully peel up the vapor barrier.

Once inside, you are looking for anything broken. If you find nothing broken, see if the motor moves at all or makes noise when you press the switch. Then post again. You will need to test the door switch and motor for electrical failure.

325i/1993 · 325i/1993's Garage

I'm talking to the all four windows here, it was just working fine and all of a sudden just stop working- all four windows! It is impossible that all of them will stop working, could it be something electronic malfunction in the system? I already checked the fuses and they are all fine. Is there a central locking device being triggered?

Manolito · 08-12-2009, 08:19 PM

Did you check the fuse?

325i/1993 · 325i/1993's Garage

Yep, but i had some doubt about my central locking switch, it could be the culprit though. Maybe its not working anymore but any idea on how to determine if it is busted or not?

Manolito · 08-14-2009, 07:42 PM

If all four windows stopped working, then the one you want to diagnose is the front passenger because that is the simplest. It does not control the other windows, and it is not on the child safety lockout. When you get that one working again, the others should work.

I am guessing that the sunroof does not work either. If the sunroof works, then the suspect is the automatic cutout. The only difference between the sunroof and the passenger window is that the power to the sunroof does not pass through the automatic cutout.

Pin #5 from the passenger window switch is a red/brown wire. It should be hot when the key is in the on position. If it is not hot, get a wire and patch 12 volts to it from somewhere. If the windows start working, follow that red/brown wire to the automatic cutout (sort of a circuit breaker). On the other side of the automatic cutout the wire is red/violet. The red/violet goes to pin #2 on the Comfort Relay.

If pin #2 on the Comfort relay is not hot when the key is on, check to make sure that pin #4 on the Comfort Relay is hot (it is the red wire from the fuse block). The brown wire on Pin #8 of the Comfort Relay should be ground, and pin #9 from the Comfort Relay should be a Violet/yellow wire that goes to the central locking module.

I am not sure, but it looks like the central locking module has to provide ground to pin #9 in order for the Comfort Relay to close and the windows to work. If the relay has power and ground, I would ground pin #9 and see if pin #2 turns on and makes the windows work. If that works, I would check the violet/yellow wire and if it is good to the central locking module, I'd replace the central locking module.