NapaC4

1991 C4 Cab

3 weeks ago the my passenger side window started acting up. The window went down just fine but when I started to put it up the window went up a couple of inches and would stop. Push the switch and it goes up another couple of inches. Passenger switch stopped working and the driver side switch was the only way to get the passenger side window up or down. It acted the same with the drivers switch (up a couple inches, stop, etc..). It worked for a couple of weeks and then died. Window wouldn't go up or down by either switch.

Then the driver side window started acting up. Went up and down fine and then one day it started to act like the passenger window - went down fine but coming up it went a few inches, stopped, push the switch, up a couple more inches, etc.. The drivers side window only did this for one day and then completely stopped working.

I do have a Viper 600ESP alarm that has the window & power locks module. The windows acted the same with the alarm. When I activated the alarm and the windows were down the windows went up a couple of inches, stopped, etc..

How she sits now: Both windows are up and won't go down. I think I have good switches (one is brand new - anyone know how to test?), just replaced the window relay, have a good 30a fuse in place, and confirmed I have power to both of the driver side passenger & driver window switches (passenger door window switch didn't have power but I'm not sure if I had the driver side switches in when I tested?? I assume you need the driver side switches in place to get power at the passenger side and I'll check this later today). Where should I start???

Places I should look?:

Window motors? Would they both go out like I described? I can pull the door skins off and check to see if I have power to the motor but I wanted to see if anyone had any ideas or things to look at before opening things up.

Viper Alarm? Not sure if a I can disconnect the window & door module to verify if it's the problem (locks work so if I disconnect the module and the locks still function with the key (unlock drivers side door and the passenger side is electronically unlocked as well) - It may eliminate the alarm module as the problem here. I may swing by the installers shop at some point and have them take a quick look but I have a feeling it would be cheaper to just have them install a new alarm!

Any and all suggestions are more than welcome on this one!

Thanks

Todd

1991 C4 Cab
1997 Land Rover Defender

jimq

Welcome to the fun

If either of the passanger window switches doesnt work the window wont work. Both need to be good.

Got any car pictures?

garrett376

The switches easily pull out of the door card - yank out your good switch, and put it on the passenger side to see if you can operate the window. It's most likely your switch has failed - happens all the time. You can clean them up and fix them as shown here:
https://rennlist.com/forums/964-forum/179410-window-switch-repair-10-minutes-and-0-amen.html

NapaC4

I have had the switches out and used the new one in all 3 spots - still a no go.

I used a multimeter to verify that I'm getting power to the switches and as I mentioned up above the driver side switches had power and the passenger side switch didn't. I'm going to retest all three and I'll make sure I have the passenger switch on the driver's side door in when testing the passenger side door switch.

I have a multimeter so I can test the continuity of the old switches to see if it's a switch problem. The driver side only has one switch and I tried the new switch in there first. Any other thoughts here?

Thanks

Todd

NapaC4

Here are a couple of pics of my 1991 C4 Cab. One in the sun and one on a foggy day at the beach. Thanks for taking a look.

Jerry Garwick

Napa

Must be a California car. Sun and Fog probably at the same time! Do you have a white interior?

I've had similar problems with my windows in a '91 cab. The switches are new and the pax window was dead in the up position after erratic operation. I finally took the damn thing apart and relubed it. It works great now but it was a big pain. BTW, my Dodge diesel truck windows never give me fits. Maybe Porsche needs to ask an American Iron maker how to make windows that work (ahem).

NapaC4

Jerry,

You guessed it - I live in Napa, Ca and head over to Bodega Bay, Ca on the coast every so often.

My general plan on this problem is to figure out what's causing the problem and fix it with the proper Porsche parts if I can. If I get it fixed and it gives me problems again then I'll replace the switches, rewire from the fusebox to the switch, and then to the motor with non-Porsche parts in order to stop the cycle of replacing the flaky parts. Sounds like the Porsche switches are prone to failure so I'm sort of already expecting to have to go the "replace" route at some point. From what I've read the window motors are pretty solid so all of the wiring, relay, & switches in between seem to be the failure points. I'll have to deal with the alarm part first before making any drastic changes.

I also have a 97 Land Rover Defender and when things act up I do the same thing - fix once with Landie parts and the second time I replace with something I know is reliable & available at my local Napa Auto Parts store. This has worked 100% of the time so I stick with it.

I was hoping someone might have a clever idea I should try in order to pinpoint the problem. Thanks for the replies!

Jerry Garwick

Todd

I'm looking at my wiring diagram for the windows and the way I see it, the switch for the driver's side and the one on the pax side should have a constant 12 v at connections 3 and 5 on the switch. The driver's switch for the pax is a bit different and should have 12 v at points 1 and 3. I won't make a life threatening committment, but I think I'm right. The switches are kind like having three, three-way switches in your house, i.e. a bit of a trick-f@#*. Don't try to figure it out after a couple of beers!

When my pax window was stuck in the up position, I had juice to all the right places and the switches were good. The dad-gum window motor just wouldn't move until I took it out and cycled it on my work bench. GRRRRRR!!!!

But other than that and a few dozen other things, i just love the car.

NapaC4

Jerry, Thanks for the info on the power and where I should be seeing it. If I remember correctly here's what I saw:

Driver side door:
driver window switch had power in 1 & 3, & 3 & 5
pass window switch had the same as above
Passenger side door:
pass window switch had power in 3 & 5 only

Looking at what you have said about the diagram and what others have commented on it sounds like I've got the right power setup (at least on the driver's side door - I'll investigate the pass side tonight to verify power). It's got to be either the switch or motor. Damn, I was hoping to not have to take the door skins off! I guess I could toss a paper clip in 3 & 5 on the drivers side window switch and one of three things would happen: blow the 30a window fuse, window goes down, or nothing happens if the motor is bad. I can also check the switches with my multimeter (Thanks to garrett376's post on the innards of the switch you can see it's a pretty simple little thing to look at).

I'll check the switches & power. If they look good I'll pull the skins and have a look at the motor. I'll check to see if it has power to it (I'm gonna start with just the driver side since it only has one switch). Does your diagram show anything in between the switch and the window motor?

Thanks

Todd

Marc Shaw

Hey, nice looking car! Are those Cup's chromed or just very clean?

Marc

darth

I have a faulty switch for the passenger side window on the drivers side(i.e. just like the one Garrett describes above and now that I read his thread on repairing it I'll do so) which I've been living with for years. When I first owned the car, sometimes it would be stuck in the down position for prolonged periods of time and when I wanted to put the window back up it wouldn't go until after a few minutes of waiting. I think the passenger side switch would work (if I remember correctly). I havn't seen a wiring diagram for the window switch circuit but just the way the switch acts after being stuck in the down position tells me that maybe there's one of those thermal fuses in the circuit which is heating up due to the switch being stuck in the down position or maybe there's a relay in the circuit which is somehow acting the same way as the thermal fuse. If there are thermal fuses in the circuit, sometimes these devices become over sensitive due to age or whatever and instead of opening the circuit at over 15amps for example, they open the circuit at some lower value which might be what you're experiencing. Typically there are micro-switches in the windows which would turnoff the power when the windows reach their physical limit but either mine are misadjusted or there aren't any in the circuit - again I havn't really looked at the circuit and these are just general observations but I hope this may help you or at least get you thinking what the problem could be.

Bill
90C2

Turbohead

If it turns out your motors are flakey i have a nice set .
$200 for both sides.
Elliot

NapaC4

OK, so I have power to the switches and power at the relay. All three switches are new along with a new relay (just got them in the mail today). I still have no power at the window motor when I flip the switches up or down. The motor works with 12v added so the motor is good as well. I'm just missing that power push between the switch & relay or between the relay and the window motor.

Anybody have any idea of what might be between the window switch & relay or the relay and the window motor????? 30a Fuse is good too so I'm running out of options to look at here!

I'm starting to think that converting to manual roll up & down windows might just be an easier solution here! Has anyone else had a similar problem?

Does anyone have a wiring diagram they can post? I have the Bentley Tech manual but it doesn't have a wiring diagram.

Thanks

Todd

darth

Adrian mentions in his book when both windows fail check fuse #4 and power window regulator (R22) for failure.

NapaC4

Darth, Thanks. Both have been checked, replaced , and double checked - fuse & relay are good.

Anybody have a wiring diagram in PDF form?