Wire for your life

[woland]

This is a short simple story but......

Both power windows worked normally
Then the fuse burned out
Changed
Burned
Took off the door switches
After short attempts the driver window worked again
"I'll see for the passenger switch during holidays".
Two months later, this was the condition of the wires near the fuel tank



In half an hour I connected a new (blue) wire trough the fuse box to the passenger door



but I remained with the sight of the fried wires
maybe they could cause a fire in the trunk during a trip
destroy the car and kill me
So next time maybe better go to see immediately
what was the cause of the short
maybe stop the car until you have found
where the short begins
Thirty years old wires can burn without previous warnings
whenever they decide

[bpu699]

Where was the short circuit? I am working on my passenger window right now... Took the whole door apart as there is no power going to the switch. When wired directly, the window works fine...

How did you trace the wiring from the window to replace it? It looks like it goes to the door jamb, middle grommet, then disappears. I cannot tell if it goes into the front trunk, or under the dash.

The easiest way to fix this is to run a new wire to the fuse panel, or possibly power it off the power seat circuit. They are both on the same fuse per the manual...

[86 911 Targa]

Originally Posted by woland

This is a short simple story but......

Both power windows worked normally
Then the fuse burned out
Changed
Burned
Took off the door switches
After short attempts the driver window worked again
"I'll see for the passenger switch during holidays".
Two months later, this was the condition of the wires near the fuel tank



In half an hour I connected a new (blue) wire trough the fuse box to the passenger door



but I remained with the sight of the fried wires
maybe they could cause a fire in the trunk during a trip
destroy the car and kill me
So next time maybe better go to see immediately
what was the cause of the short
maybe stop the car until you have found
where the short begins
Thirty years old wires can burn without previous warnings
whenever they decide

These types of issues can be due to the harness failure from opening/closing the door(s).

Assuming you have a Bentley and a multimeter, continuity checks will have to be performed to find the open/shorted circuit.

If It's in the door harness, pulling a new wire will take some time.

Here is the circuit.

[86 911 Targa]

Originally Posted by bpu699

Where was the short circuit? I am working on my passenger window right now... Took the whole door apart as there is no power going to the switch. When wired directly, the window works fine...

How did you trace the wiring from the window to replace it? It looks like it goes to the door jamb, middle grommet, then disappears. I cannot tell if it goes into the front trunk, or under the dash.

The easiest way to fix this is to run a new wire to the fuse panel, or possibly power it off the power seat circuit. They are both on the same fuse per the manual...

The wire goes to fuse #1 then the P/W relay.

[86 911 Targa]

Originally Posted by bpu699

Where was the short circuit? I am working on my passenger window right now... Took the whole door apart as there is no power going to the switch. When wired directly, the window works fine...

How did you trace the wiring from the window to replace it? It looks like it goes to the door jamb, middle grommet, then disappears. I cannot tell if it goes into the front trunk, or under the dash.

The easiest way to fix this is to run a new wire to the fuse panel, or possibly power it off the power seat circuit. They are both on the same fuse per the manual...

I just pm'd you.

[Hodgey]

Originally Posted by 86 911 Targa

I just pm'd you.

Hello Gerry...I just PM'd you...hope you don't mind...and I apologise for mis-spelling your name

[woland]

Hi bpu699

Everytime something happens in my 1980SC I realize that Porsche is logical as the consecutio temporum: You have simply to follow the path of the wires. Remember that when a line pass through a surface, you will find a plug: The circuit is sectioned in more parts.
In the case of power windows the path of the wires is the following - driver window:

- From power window to switch
- From the switch through the side of the door to a plug under the fender
- From the plug to the upper right inside of the trunk; then the wires run under the fuel tank filler to the fuse box.
My fried wires were here. I found it touching and moving the bundle after removed the ties

The passenger door wires follow the same path and use the same fuse then go horizontally to the other side of the trunk running under the front blower.
There's another plug under the fender, then the switch, then the power window...

Remember
Always work on it with the battery (+) unplugged

[bpu699]

Thanks guys, I plan to look at it over the next couple days...

I suspect the relay works, as the drivers window works (is this correct?)...

The drivers side passenger switch also has 12v at positions #5 and #3...

Changed the switches, made no difference.

So, somewhere from the drivers passenger switch to the passenger window, there is a disconnect...

Quick question on the wiring diagram in Bentley... something doesn't make sense. It looks like the drivers side passenger switch and the passengers side switch are in series?!

IE. When one flips the drivers side passenger switch it would send 12v to the passenger side switch (points #3, #5)... But if the passenger side switch also isn't activated (up/down) then no power gets to the window motor? I would think that the output from the drivers side passenger switch should go to the passenger window motor directly, not through another switch?

Any electric gurus get what I am trying to grasp? If I take a wire and tap it to the battery, and then splice to positions #3/#5 on the passenger side, the window works perfectly... This means the switch works fine, right?