Need some electrical advice-windows and heater

ChemMan · ChemMan's Garage

Let me preface this with two things. First, I did do a search and second I am obviously no expert on electrical systems.

I have a 1986 carrera

Last summer/fall, I tried to roll down my windows and they would not work. I turned the dashboard controls on for the fan and a puff of white smoke came through. I ended up driving for a couple more weeks, it was cool anyway so I did not need the fan or to have the windows down. I am now getting my 911 out of storage. This is what is happening:

1. Fuse 1 (power windows and sunroof) keeps blowing
2. The dash controls for the fan do not turn anything on. The footwell and AC controls in front of the stick shift do.

I am not sure how to approach fixing this. I followed the instructions in the Bentley manual and removed the fuse and checked the voltage at that location. It read 12.35V, same as the battery. The manual does say to disconnect the item being tested, but I am not sure how to disconnect the power windows. Sorry if this is a dumb question. Any advice you can give me would be appreciated.
Thanks,
Mike

DaveE · 03-09-2006, 10:52 AM

You'll have to remove the door panel. I'm not too familiar with your power windows but there may be a plug at the PW motor you can unplug. That or they just use fast-on connectors for pos and neg at the motor. Disconnect, then test and see if the fuse blows. If it doesn't, then the motor's shorted. If it does, then it could be in the wiring. I don't have a schematic in front of me but if there is a connector somewhere between the fuse and the actual door you can unplug that too to aid in your troubleshooting. Bear in mind I don't have a schematic in front of me to see how your windows relate to your dash fan. Are they on the same fuse / circuit?
Good luck.

Mysterytrain · 03-09-2006, 12:24 PM

I think the wiring from the doors goes into the corners of the trunk and plug into the main harness. You should be able to unplug both of the door harnesses and put the fuse back in place. Then plug ONE of the door harnesses back in and see if the fuse blows. Then plug the other one in. The one that blows the fuse will be the door panel to remove and dig into. I would love to see a picture on the locations of the plugs in the trunk. I'm planning to go from manual to power one of these days.
The plugs are shown in red...

As for the other problem, are you saying the fresh air blower [dash controls] is not working but the A/C and heating systems are?

ChemMan · ChemMan's Garage

Thank you for your advice.
Dave,
According to the sticker on the fuse box cover, fuse 1 is only for the power windows and sunroof. The bentley manual says for heated seats as well, but I do not have that option.
Ron,
Yes I am saying that the fresh air blower is not working but the other two are.
I am going to try to do what you guys suggested this weekend. Hopefully I can figure this out. Funny thing is that the PO (who owns a Porsche Performance Shop) replaced the driver side window motor right after I bought it.
Mike

Mysterytrain · 03-10-2006, 05:33 AM

While you are digging around in the trunk you can also examine the fresh air blower. Remove the carpeting. Then remove the fiber board that covers the back of the dash. That big ol' plastic housing is where the blower lives. You can pull the connector off and look for power on the connector, also check for a good ground. Those the blowers do go bad.
You might have a pinched wire on the drivers side. I think the power feed goes directly from the fuse to the pair of switches.
Mike, If you have a digital camera I would appreciate a picture of the location of the sockets (red in the earlier post). Thanks