Window fault

[munkymanmatt]

Ok, so I've a problem with my front passenger side window and haven't got a clue what it is.
I have changed the switch for one I know works perfectly and the problem remains.

When I push the switch to open the window, it opens by about 2cm and then stops, no matter how long I keep holding the switch it won't go down any further. It takes multiple presses to get the window to open fully. It closes normally i.e. press and hold the switch and the window closes in one go at normal speed.
Sometimes, when I try to open the window, if I hold the switch for more than half a second, the window opens by 2cm and then closes itself all the way automatically.

I have disconnected the driver-side controls for this window as having that switch connected made it worse. When that switch was still connected, every time I started the engine the window would open itself by 2cm without me touching any window switches. Occasionally, if I had the windscreen wipers on and used my left indicator at the same time, the window would open by 2cm every time the indicator lights came on, again without me pressing any window switches.

I have no idea what might cause this, can anyone help?

[steve_earwig]

Holy crap that's weird! Window, wiper and indicators? Possibly an earth fault (but then I'd have thought all three would be earthed in different places - unfortunately I don't have any wiring diagrams for a D8 that I'd like to rely on) so I think I'm going to go with a crushed/damaged cable.

Which switch did you change?

[munkymanmatt]

I unplugged the driver's side switch and left it that way - it was like that when I bought the car, I reconnected it and found it why the previous owner had unplugged it!

Then I pulled the switch from the rear n/s window, which worked perfectly, and plugged it into the front passenger window slot, and the same fault was there, so it can't be the switch!

[steve_earwig]

I still don't get how the wipers and indicators could have an effect on the window: ignition ok, lights, maybe but... I reckon I'd start off looking at the wiring loom, as much as possible above & around the fuse box, paying close attention to anything that's not standard.

I'd also want to put a meter on the window motor feed and see just what it's getting , particularly when it's reacting to the starter, wipers & (dear god!) indicators.

[munkymanmatt]

Yeah, going to go exploring under the glove box during the week for the wires, I'm not really sure of how to get at the window motor, I don't have a haynes manual either! I've found some dodgy wiring in the rear passenger side window too though, a few wires seem to be broken somewhere in the door. Maybe some of the wires' insulation has cracked and they are crossing.
Probably a silly question, but does the ECU have anything to do with the windows?

[steve_earwig]

Which ecu? It's a D8 so no BSI or any of that sillyness to worry about.

[munkymanmatt]

Not sure. Thought I might have read something on here about someone's ECU messing with their windows. That could have had something to do with anti-pinch or the one touch feature or the windows on a D9 though.

[munkymanmatt]

Could a faulty window regulator cause something like this?

[steve_earwig]

I don't think so, how would it pick voltage up from the wipers & indicators?

[munkymanmatt]

Well I'm thinking perhaps there are wires crossing somewhere down the line causing that. the window gets pulses of power at the exact same time the indicators light up, so thats the only explanation I can think of. That's only when the driver's side switch is connected though.

What I want to focus on first though is why the window won't open properly when using the passenger side switch. The way it stops and starts and sometimes closes itself after you try and open it, I don't know what that could be.

[steve_earwig]

Me neither, but if it's wired up like a D9 with the driver's switch removed it shouldn't even work at all.