Porsche Repair: Driver power window, trouble shooter, ground path

Question
Hi Dave
The drivers side power window quit working,going up.it powers down only.
I pulled the cover and found the motor would only run in one direction, thinking the motor is bad.
I bought a used one off Ebay that was suppose to be good.
it also only runs one direction, down.
I checked with a volt meter and have 12+ at both motor termnals,all the time when the window sw. is not pushed.
when I push the sw I have 12+ at one and 0 at the other,
i reversed the two termnal wires and it will then run in the up direction.

I have 5 wires going to the window sw.
I was a electronic trouble shooter 35 years ago,

and still know some, but not about power windows without a wiring scymatic.
Thanks for any help.
Ed

Answer
Hi Ed,

An electronic trouble-shooter and you're askin' me a question?  C'mon, am I on Candid Camera?

OK, so I've got a wiring diagram.  It's for a 85-ish 944.  You didn't say 911 so I'm taking a chance on the 944.

Your five wires at the switch are:

1. Blue to motor, 12v+ with switch at rest
2. Blue/White to motor, 12v+ with switch at rest
3. Brown ground
4. Red/Blue, when switch is activated, 1. Blue is disconnected from power, Red/Blue provides ground path for motor
5. Red/Green, when switch is activated, 2. Blue/White is disconnected from power, Red/Green provides ground path for motor

You'll know what this means better than I, but the motor reverses polarity and its direction depending on which contacts of the switch are broken.  I suspect either the switch is faulty or more likely just gunky dirty.  Gunky dirty is mechanic talk, ya know.

You've proven the motor is A-OK, give that switch a good look.

Dave