Sunroof electrical issue - advice would be very welcome!

[Chopperharris1975]

Hi everyone

 

Long time 997.1 C2 owner here based in the UK.

 

I’m hoping someone can guide me on a diagnosing my sunroof issue. Sunroof does not respond at all - below is a list of things I have done so far:

1) Replaced switch with new item.

2) Tried 2 different motors - used but sold as ‘tested'.

3) Tested wiring harness to motor/switch: Pin 6 ground ok, Pin 5 has 12v, Pin 3 (close) continuity to pin 4 on switch, Pin 2 (open) continuity to pin 2 on switch, Pin 1 (lift) continuity to pin 1 on switch.

4) By apply 12v to the motor (installed but with control module discounted) the roof will open and close with no issues so frame/motor is ok.

 

I notice on the wiring diagram that pin 3 on the switch routes to pin 15 on the ‘control unit rear’. I can’t make out what this connection does as the pdf wiring diagram I have (for this sheet only!) is not clearly legible. It says something like  Sun roof enabling signal’. No idea if this is ground signal to tell the control unit when the sunroof is opening or something else? Could this be the route to my issue? 

 

Any guidance would be gratefully received as this one has got me stumped!

 

Many thanks

Ben

 

Snapshot of wiring diagram below.

 

 

 

 

Edited June 24, 2022 by Chopperharris1975
update

[Chopperharris1975]

No many response so I assume i must be alone with this issue.

 

For future reference i’ve worked out what the issue is plus found a workaround.

 

The enabling signal mentioned above is a 12v that is sent when ’sun roof’ is coded as an option. My car had a full engine rebuild (bore score) a couple of years ago and when I got it back the heated seats had stopped working - this was due to it being disabled as an option. To resolve I had to get the specialist to re-enable with PIWS. Given there is no 12v signal being sent to pin 3 on the sunroof switch I can only assume that I also need to get the sunroof enabled so will get this checked at the next service. As a work around I’ve temp re-wired pin 3 to a switched power source (anti glare mirror - brown/orange wire). I now have a working sunroof. I’ll revert to factory set up asap to avoid future owner confusion!

 

 

 

 

Edited June 27, 2022 by Chopperharris1975