Driver's Side Window Problem

[Silntknight]

Hey, I have an e36 convertible where the driver's side window works intermittently. First off, yes, I have searched pretty extensively about this, but my problem seems different from other peoples'. For me, the window occasionally works just fine, but suddenly, it does a partial retract, like if it sensed that there was an obstruction. After that, the window doesn't respond to the switch for some arbitrary amount of time. This varies. I've had days where it starts working again within five minutes, and other times where it takes a few days. Also, it only ever stops working when it's going up. It never hangs while retracting, though once it freezes, it doesn't move either direction.

I took off my door card to get a better view of the regulator. The slides all look good and greased, and since it moves occasionally, I know the electrical system is fine. I tested whether it was a problem with switch contacts by replacing the switch with the front passenger window switch, but it had the same issues, so the switch is fine.

I suspect that there is a problem with the system that detects obstructions and stops the window from closing. When I press the switch, I briefly see voltage on the motor power leads, and I can hear (from the glovebox area) a relay closing, but almost immediately reopening. Unplugging the sensor wires seems to, occasionally, allow the window to move either up or down in very small steps, but it quickly freezes when I do that too.

Does anyone have experience with the window obstruction sensor system, or are there other troubleshooting steps I can take?

Thanks!

[Fitguru]

Hey, I have an e36 convertible where the driver's side window works intermittently. First off, yes, I have searched pretty extensively about this, but my problem seems different from other peoples'. For me, the window occasionally works just fine, but suddenly, it does a partial retract, like if it sensed that there was an obstruction. After that, the window doesn't respond to the switch for some arbitrary amount of time. This varies. I've had days where it starts working again within five minutes, and other times where it takes a few days. Also, it only ever stops working when it's going up. It never hangs while retracting, though once it freezes, it doesn't move either direction. I took off my door card to get a better view of the regulator. The slides all look good and greased, and since it moves occasionally, I know the electrical system is fine. I tested whether it was a problem with switch contacts by replacing the switch with the front passenger window switch, but it had the same issues, so the switch is fine. I suspect that there is a problem with the system that detects obstructions and stops the window from closing. When I press the switch, I briefly see voltage on the motor power leads, and I can hear (from the glovebox area) a relay closing, but almost immediately reopening. Unplugging the sensor wires seems to, occasionally, allow the window to move either up or down in very small steps, but it quickly freezes when I do that too. Does anyone have experience with the window obstruction sensor system, or are there other troubleshooting steps I can take? Thanks!

I'm having the same problem. I'll be watching for an answer.

[shadowpuck]

Actually. Pretty common problem. Likely a problem with the door micro-switch.

[Silntknight]

Actually. Pretty common problem. Likely a problem with the door micro-switch.

Can you elaborate? If I understand you correctly, the microswitch would signal whether the door is open or closed. Why would that interfere with the ability to raise and lower the window (since it should be able to do that in both cases), and why would it get stuck where it won't move for days? Also, if it's common, do you know if anyone has posted a solution? I haven't seen one yet...

Any other diagnostic tips you can give me would be awesome too. I'm doubtful about finding a solution after not seeing one for so long, so I am going to be trying to solve it myself.

[MarcoZandrini]

I know that the E46 chassis has the General Module 5 (GM5) for windows, central locking, etc. I believe the E36 has the GM4 module. The GM5 module is full of relays that can act intermittently. I think I'd check that if all else fails.

In the E46 there's a switch in each door lock actuator. A bad switch could impact (not 100% sure) window ops.

[shadowpuck]

i may have also mis-read your original post - so apologies there.

it sounds like you are describing the one-touch up operation. google/forum searches should produce numerous hits on how to troubleshoot and test this operation. have you tested for voltage at the switch while you were having the problem? i'm thinking things like weak relay, fuse, or even the motor itself - since you mentioned that when it fails you lose control for an arbitrary period of time.

i have heard of micro-switches causing all sorts of weirdness, too.

[bmwdirtracer]

The E36 window regulator is much more reliable than the lousy cable and plastic pulley arrangement of the E46....BUT, when it does fail, it's more of a problem to diagnose and replace.

Your best first step will be to remove the door glass from the regulator. (It would be a good idea to pick up two of the white plastic window slides from your local dealership) Removing the glass will remove much of the strain from the motor and the regulator. If the problem goes away, replace the motor and regulator. If the problem continues, you have an electrical issue. If it's an electrical issue, first suspect will be the wiring in the door hinge are's rubber boot.

[Silntknight]

I know that the E46 chassis has the General Module 5 (GM5) for windows, central locking, etc. I believe the E36 has the GM4 module. The GM5 module is full of relays that can act intermittently. I think I'd check that if all else fails.

In the E46 there's a switch in each door lock actuator. A bad switch could impact (not 100% sure) window ops.

I'll look into this a bit more. The GM4 is certainly in the right place (behind the glove box), and perhaps the relay only works sometimes, which is causing the issue.

i may have also mis-read your original post - so apologies there.

it sounds like you are describing the one-touch up operation. google/forum searches should produce numerous hits on how to troubleshoot and test this operation. have you tested for voltage at the switch while you were having the problem? i'm thinking things like weak relay, fuse, or even the motor itself - since you mentioned that when it fails you lose control for an arbitrary period of time.

i have heard of micro-switches causing all sorts of weirdness, too.

I'm actually talking about any type of operation, one-touch up/down, or hold up/down. I've only tested voltages at the motor terminals. I unplugged the motor and tried operating the window. I would read around ±12V when it worked, depending on if I pressed up or down, and a brief spike before 0V when the window wasn't working. Basically, even with the motor itself disconnected, the system showed that it momentarily tried to send power (relay closing sound I heard) before cutting it (relay opening sound I heard).

The E36 window regulator is much more reliable than the lousy cable and plastic pulley arrangement of the E46....BUT, when it does fail, it's more of a problem to diagnose and replace.

Your best first step will be to remove the door glass from the regulator. (It would be a good idea to pick up two of the white plastic window slides from your local dealership) Removing the glass will remove much of the strain from the motor and the regulator. If the problem goes away, replace the motor and regulator. If the problem continues, you have an electrical issue. If it's an electrical issue, first suspect will be the wiring in the door hinge are's rubber boot.

I'll try that. I've already gotten the door card out (the PO secured it with a wood screw and a few of the bottom tabs...), so it's only a few more steps. I was first going to try removing the motor from the regulator assembly and testing if it spins freely when removed. I was having problems with my convertible top and I noticed a motor retention plate was bent, likely causing the problem, so I wouldn't be surprised if other motors were misaligned, causing increased loads. Hopefully this will tell me if it's mechanical or electrical!

[325ed]

I know that this is an old thread, but did you manage to fix this? I think I might be having the same problem as you had.

Thanks!