Power window problem - bmw e36 318i 1991 sedan

[B.H.11]

Hello community, i have one question...
Sometimes when i turn the car on the power windows do not function, after some time, 1 min? or less maybe, the windows work normal up and down... any clue what causes this? And i think it only happens in the summer...
Thanks!

[Eric93se]

What's up bh11, welcome to the forum!

One thing you can do is remove the motor and take it a part, over time the brushes leave caked on carbon on the commutator (copper ring the brushes run on) thoroughly clean the ring with brake or carb cleaner till its nice and shinny.

When disassembling you should note the marks on the motor cover, if you install it backwards the motor will run reverse. After opening the gearbox there is only one c-clip holding it together, the whole motor and worm gear will slide out with some wiggling and gentle lifting of the large gear.

[AJLM34A]

Hello community, i have one question...
Sometimes when i turn the car on the power windows do not function, after some time, 1 min? or less maybe, the windows work normal up and down... any clue what causes this? And i think it only happens in the summer...
Thanks!

I am assuming you have a early 4-door E36, and the problem happens to all four windows at the time?

My guess is the harness on the back of the ignition is worn/wearing out. You can test to see if when the windows do not work when ignition is on, do you work from the drivers door lock with the key?

First place to start is the wiring diagram to see what circuit they are on. The motors are told what to do by the GM, the GM gets a signal from either a windows switch or keyed door lock. The GM gets power from relays, relays get turned on/off from the ignition.

[shogun]

wiring diagrams are here http://wedophones.com/BMWManualsLead.htm

[B.H.11]

I am assuming you have a early 4-door E36, and the problem happens to all four windows at the time?

My guess is the harness on the back of the ignition is worn/wearing out. You can test to see if when the windows do not work when ignition is on, do you work from the drivers door lock with the key?

First place to start is the wiring diagram to see what circuit they are on. The motors are told what to do by the GM, the GM gets a signal from either a windows switch or keyed door lock. The GM gets power from relays, relays get turned on/off from the ignition.

Yes the early 4-door E36.

Ok thanks. Do you mean by "do you work from the drivers door lock with the key?", having the windows down and then close the car by the door lock rotating 90º to right? Then no the windows do not close, and the door lock motor has been changed due to not closing the car.

[B.H.11]

What's up bh11, welcome to the forum!

One thing you can do is remove the motor and take it a part, over time the brushes leave caked on carbon on the commutator (copper ring the brushes run on) thoroughly clean the ring with brake or carb cleaner till its nice and shinny.

When disassembling you should note the marks on the motor cover, if you install it backwards the motor will run reverse. After opening the gearbox there is only one c-clip holding it together, the whole motor and worm gear will slide out with some wiggling and gentle lifting of the large gear.


Thanks! I don't think it necessary, because the buttons do not light up, after the minute when the window work they light up... and if i need to clean the motor it would be 4 motors!

[AJLM34A]

I've only looked through US spec wiring diagrams and early cars might not have the drivers door key window control function. The early US cars have an overload protection so a Euro car could too.
The best and cheapest way to figure this out is with the proper ETM(wiring diagram acronym).

The window switch lighting is usually grey/red wire and it is on the dimmer circuit.

[B.H.11]

Ok thanks. Then i think is the harness on the back of the ignition is wearing out as you said
AJLM34A (https://www.bimmerforums.com/forum/member.php?412820-AJLM34A)
, if it connected too to the dimmer circuit because both turn on, windows and button light, after the minute.