Geojerry

The passenger side window button on console of my 91 S4 clicks
And nothing happens. Window does not go down. No motor noise in panel. Driver side ok.

I saw a lengthy thread on this somewhere on this forum.
Suspect it may be the switch. Any help would be appreciated.

Thx, Jerry

westija

Give these a try

You can also do a search on Rennlist using "window" and selecting the 928 Forum. If after checking these you find the problem is with the motor search the DIY and see a procedure on Motor repair

http://www.nichols.nu/tip532.htm

http://www.nichols.nu/tip165.htm

http://www.kondratyev.com/porsche/te...ndow_frame.htm

http://members.rennlist.org/pirtle/keepers.html

mickster

1. Check the switch
2. When the car is on you should hear a click from under the driver's seat when you push the button in either direction. That would mean the switch is engaging and hitting the relay (under the driver's seat) but that you may not be getting voltage at the motor.
3. If you don't hear a click you also can try this with the car on-if you click and hold down the down side of the passenger switch, immediately try to either open the sunroof or the driver's window. If they open/go down then you probably have just a bad switch, although it could be more. If the relay is energized it will not let the sunroof or driver's window open (to keep amps down).
4. Next you have to get the door open-follow the write-ups above.
5. Once inside the door check for 12 volts by removing the connector for the motor. That is critical; good chance the motor windings are toast or the brushes are toast and you'll need a new motor. You can replace it without removing the regulator but it is a bitch.

Here's how to open the door: http://www.landsharkoz.com/forms/928...el_removal.pdf

SQLGuy

One other possibility is broken wires in the door. I think this is less likely in the later cars, though, since Porsche changed how they route and fasten the wires. In the earlier S4's the wires would often break where the bundle exits the heavier sheathing just inside the door panel. Sometimes this would break the wires' insulation as well, but other times just the strands inside would be broken. I've seen this with door motor wires and speaker wires.

BTW, checking 12V at the motor means connecting both probes of a digital meter to the two pins of the motor connector and pressing the window switch. Depending on which probe is on which pin, and which direction is pressed, you should read about +12V or -12V.

Orantes

I would say switch. Mine did the same thing. Could hear a click and then nothing. Sometimes I could hit the switch a few times and it would work. These switches are inexpensive from 928 Inetrnational and if yours are original, they probably need replacing. Do both switches at the same time for peace of mind. Having an inoperable window is damn annoying!

SQLGuy

The switches are a less likely failure point on later cars, like the OP's '91, because they no-longer power the motor directly. Instead the motors are powered through relays in a module under the driver's seat. In the older cars, the current draw through the switches was enough to heat the contacts and cause them to melt into the base of the switch... eventually they would be too low to make contact any more when the pad was pressed.

dfrhodes

Having repaired my window switches several times now, i'm fairly confident the contact failures are due to arcing, not by current heating (assuming your contacts are pitted and black as mine used to get).

Basically, when the switch opens and power to the window winder is removed, the field in the motor collapses, inducing a spike across the switch contacts ( similar to old ignition breaker points)

Cheap solution - transient voltage protection, like those varistors they sell at Radio Shack.

i'm not sure if they are included on motors in later models, but simply adding relays to the circuit just moves the arcing problem to the relays.

d

SQLGuy

I'm guessing Porsche did more than just move the problem to the relays, as the window control module in the later cars does not seem to be a common failure item.

In my '85 S, the behavior I observed was that the switches had to be pressed harder and harder to work. When I opened them, I found the contacts had melted down into the plastic base until they were flush with the plastic. Arcing will increase their resistance, which will cause more heat. You're probably right about flyback being an initial cause of contact damage that leads to this cycle.