Passenger power window problem
 

I'm hoping someone can narrow down my problem so I can search this forum more efficiently about the cause of my problem. I have an '89 Carrera and the passenger power window intermittently quits working.

When it quits working neither the drivers side passenger window switch nor the passenger side window switch operates the window. The drivers window and switch are never affected. Only the passenger window.

Randomly, the window starts working. When the window begins working both passenger switches work as normal. I read a post here that indicated that power comes through the passenger side switch. That might explain why both passenger switches fail or work at the same time.

Is my problem likely a relay, the passenger window switch, the motor, or something Bentley calls the power window control module (wherever that's located)? Where do I begin? Thanks for any help.

Sounds like the motor/regulator need replacing. Take a look at the link below to our site's DIY tech article on this procedure. Please let us know if you have any questions!

Porsche 911 Window Regulator and Motor Replacement | 911 (1965-89) - 930 Turbo (1975-89) | Pelican Parts DIY Maintenance Article

P/w
 

You are close with the power routing.

Let's have a look at the P/W fuse first.

Clean the fuse contacts, and replace the fuse.

Then report back as needed.

Best,

Gerry

is there a separate left and right fuse ??

Just a single fuse but always a good place to start, I solved many electrical problems with cleaning the contacts and replacing the fuse. The window switches fail often, have replaced mine twice.

Have the same problem with my '88. Intermittent passenger window problem. You can use a DMM to make sure power is there. If it is, you've got a mechanical problem.
As your is an '89, you probably have a hex key in your toolkit that fits into the window gear that's hidden behind the (upper) door speaker. Remove the speaker grille to find it. I think there's a pic in the manual. Use the hex tool to wind the window up or down. Don't be surprised if it starts working. Mine acts up occasionally and that's how I free it up. Have also freed it up by banging the door panel in that area while operating the switch. Kinda like banging on a starter to make it work. In my case, I could replace the motor that's acting up, but some day......

Thanks guys. I'll clean/replace the fuse but figured that might not be it since there's only one fuse and the drivers side works. Certainly won't hurt to start with the basics.

Since it's intermittent, when it's not working and I have power to the motor it seems to follow that the motor would be the problem, right? Conversely, when it is working I wouldn't be able to tell much. I do have a Power Probe so I could supply 12V to the motor several times to see if I can get it to fail.

I knew about the tool kit for emergencies. Fortunately it has always started working after driving around a while so I haven't needed to use it. I guess that equates to banging on the motor...

All window power goes to the passenger's window switch located on the driver's door. From there it goes two directions - it jumpers to the driver's window switch, and it also goes back into the frunk and across to the to the passenger's side switch. There are white circular connectors in the frunk near the front edges of the door. They house the power window wiring. You can wring the wiring out there probably easier than opening your doors up if it gets to that stage.

I would gently pull out the passenger's switch on the driver's door and carefully check power (in and out) there. That will tell you if your switch is working properly. Looking at the passenger's switch on the driver's door, the incoming power is Red/Blue (switch pin 5 and jumpered to pin 3 then to the driver's switch pin 5. Red/Black on pin2 and Red/White on pin 1 are the outgoing power to the switch on the passenger's door before it makes it way to the motor . One of them will have power on it depending on which way you are commanding the window up vs. down. Use a local ground at that door, or the brown wire connection at pin 4 of the switch if you can, to check the operation of the switch.

I borrowed these photos from some nice person on this site:

http://forums.pelicanparts.com/uploa...1495498095.jpg

http://forums.pelicanparts.com/uploa...1495498095.jpg

http://forums.pelicanparts.com/uploa...1495498095.jpg

Then I would do the same at the switch at the passenger's door. Here, when the Red/White carries power at pin 3 it will exit the switch to the motor on Blue wire at pin 1. When the Red/Black wire at pin 5 carries the power, it will exit the switch at Blue/Black pin 2.

The ground probably isn't the issue based on your description because there are separate grounds closer to the door and would only affect that door switch.

Based on what you read at each switch you will give you an idea of where your issue lies.

If it isn't the switches, then the next step would be to check wires. Those circular connectors make it relatively easy as they isolate the wires near and in each door and the wires across the funk. More than likely, if it is a wire, it is door related. Mine were corroded inside the door but I would imagine that the wires also get worked every time you open and close the door and could cause an issue over 30-ish years.

P/w.
 

Yup,

These are my pics.

Gerry

Definitely check the switches as they do produce the problem you are describing.

Pw ckt.
 

http://forums.pelicanparts.com/uploa...1495556104.jpg
^^^^^
From my factory manual.

pm me as needed.

Best,

Gerry

Many thanks for the diagrams and instructions in plain English for us schematic/electrically challenged people. I need time to think this through but we're going on vacation and I won't get to it for a while. Besides, if I'm looking at this correctly I need to diagnose this when the problem is actually occurring. Otherwise everything will test OK. Correct?

I plan on using my Power Probe to simplify testing. The ground of the Power Probe will connect directly to the battery negative. That way I can just test for voltage, with the key on, at the proper points to see if it's flowing per the diagrams. IE- power to the switch itself and when toggled up/down per the instructions.

Since this is a common problem should I just cut my time and replace both passenger door switches for about $100. I assume the non-Porsche/OEM switches for $17 are not worth it. Probably China or other cheapo quality?

Pw
 

PM me prior to any intrusive analysis.

Gerry

Stay away from cheapo switches. The contacts on them break off and then you're right back where you were.

You'll be throwing your money away on switches if it's not a switch problem. Verify first. I'm thinking you're going to find out it's a mechanical problem with the motor: it's binding up from time to time. May be able to cure it by removing it & taking it apart & cleaning & re-greasing it.

While I'm generally not a fan of the shotgun approach to diagnosing problems, given how frequently these window switches fail, it's not a bad idea to rule out a faulty switch first. This could be done by buying (or borrowing) a single replacement switch. Specifically, replace the switch on the passenger door and see if this rectifies the intermittent problem. If it does not, swap the wires on the 2 driver's side switches (since the driver's door window consistently works fine and is known-good) and see if that fixes the problem. If it doesn't, put all back to original and store the purchased switch as a spare to replace one of your existing switches when it (inevitably) fails

I just went through this intermittent failure mode on my passenger window.
What I did was to pull all the connections off both the drivers and passengers window switches one at a time and made sure they were clean and tight.
After that I sprayed some contact cleaner in the switches (you can do it from the front of the switch with it in the up and down position which allows you to spray inside). Once sprayed I rocked the switches between the up and down positions to clean the contacts.
Need less to say I did all this with the key off and battery disconnected and waited 30 min or so for the switch to dry before trying the switch.
While I was at it I also did the drivers switch (ounce of prevention and all that)
Seems fine now.
If this doesn't work try what Darren said above about swapping the drivers and passengers switch.
Terry

If all else fails, as a long shot, look at the connectors in each of the door/fender cavities. Picture below.

I had a similar problem (both driver and passenger windows didn't work) and found the connector was loose causing an intermittent connection. I'm pretty sure that connector routes the power & grounds to the window switches.

Worth a try.

http://forums.pelicanparts.com/uploa...1503591152.jpg

Window switches.
 

http://forums.pelicanparts.com/uploa...1504495659.jpg
http://forums.pelicanparts.com/uploa...1504495693.jpg
http://forums.pelicanparts.com/uploa...1504495713.jpg
^^^^^
All window switches wiring.

Re-orient a switch by 180 degrees if the up/down functions are reversed.

Or, swap the wires on post 1&2.

G.