Power window question.
 

My '88 Carrera has an intermittent problem raising the passenger side window.

Driver's side window/switch always works fine. The passenger side down function always works from either left or right switch. When this happens neither the left or right switch will run the passenger window up, only down

Randomly the next time I drive the car all is fin.e

Haven't yet looked at the diagrams but this seems an impossibility.

Random usually means a loose wire somewhere. Probably between the motor and passenger switch as both switches work when they work. (Coming from common terminal on switch to motor)

Wires, not "wire"....

The same wires between the switches and the motor are used for both directions

Each side has a DPDT switch, and BOTH switches have power and ground cross-connected with pole sides connected to the motor else down function would not work.


:confused:

The problem might be a loose connection in the driver's side or in the passenger's side. I found the following link particularly useful when dealing with these electric windows.
http://forums.pelicanparts.com/porsche-911-technical-forum/288567-power-window-switch-schematic.html
(scroll down the image, there is a complete circuit schematic in the second part)
Good luck
Jose

The easy thing seems to be checking the connections at all 3 switches. Once you've verified those connections, then comes the work. Taking off the door card and verifying connection at the motor. Sorry I can't be more help but that's how I'd tackle it.

Come to think of it, isn't there a power window relay? I'm not sure but thought there was. I'll try to check my diagram later. But if there is, I think I'd start at the relay for intermittent problems. I know how the wires are packed in the door pocket and the odds of one coming loose are slim to none in my opinion unless someone messed with the switches recently. I don't recall how they connected to the motor.

Again, the power and ground to both switches is good, as is the switch(es) to the motor is good.

Power window down, both switches, works, power window up, both switches, does not

If you help the window on power up with your hand and it works it might indicate a weak motor. I had a similar issue and replaced the motor in my 78.

You mean, intermittently good.
You might have some problem with the action or contamination with one of the switches (I've experienced this) - I've also read that the harness in the vicinity of the door penetration can get wonky.

From you in your OP "Randomly the next time I drive the car all is fine"


Okay, I'm out.

No help...

Don't forget to check the plugs in the upper fender area. I had an intermittent problem and it was solved by unplugging the round plug in the drivers side fender, cleaning it and plugging it back in.