dnlwtsn

My sunroof will lower but will not raise. After days of poking terminals with a multimeter and recently following this electrical diagram, I think I have isolated the issue.

The sunroof microswitch ('Position switch' towards to bottom right on the below diagram (Porsche 944 Volume 4 - Electrical Page 213) located in the roof area is not receiving ~12V on the yellow wire from terminal 4 on the sunroof switch 'lifting roof control switch' when I bridge terminals 2 and 4 whilst the key is in the ON position (This I think simulates the pressing down of the sunroof up button). Additionally, there is no continuity between terminal 4 and the sunroof microswitch. The microswitch itself is fine. According to the diagram, there should be a complete circuit here. I'm using a bolt from inside the car as ground, which seems to give a voltage readout for terminal 2.

I have tested the rest of the motor assembly at the back of the vehicle, the relay at the front (AFAIK sunroof switch terminals 1 and 2 should not receive any power without a working front relay) and the relays at the back. I have applied the required voltages to the terminal on the motor assembly and I think I have been able to operate the motor in both directions this way. There is ~12V to the terminals 7 and 4 when the key is ON and the sunroof raise button is pressed but not to pin 8.



Looking at the wiring as much as I can without pulling the whole front of the interior out, it looks like somebody has already done a number to it; snipped connections to god knows what and installed a custom speaker system, it wouldn't surprise me if there's a burned or broken connection behind it.

I'm not familiar with electrical diagrams like this (This is the first one I've read) so before I go ahead and try to pull out whatever parts I need to access the harness, as test, I'm going try to connect pin 2 or 4 directly to the microswitch with a long wire and see if that helps prove my current hypothesis tomorrow hopefully.

Have I missed anything to check? Are there any useful guides on accessing the internal portion of the wiring harness to help me look for physical connection issues between the sunroof main switch and the microswitch yellow wire?

orig944

Read this:

https://forums.pelicanparts.com/pors...-diagrams.html

NoRush993/951

While raising the roof panel, take your thumb and lightly press the underside of the black micro switch that is above your head in the middle front of the panel. This contact loses connectivity over time. A little manual assistance might work for you and get this to go.

dnlwtsn

Managed to make a new discovery. Someone has completely snipped the wiring loom connecting the interior light and the sunroof switch. This would explain why the sunroof didn't work. But why??

Petza914

Gotta love POs.

dnlwtsn

I managed to remove the dash today and expose some more wires but I'm still clueless as to where that snipped wiring loom from the roof lining came from that belongs to the microswitch for the sunroof. I really want to pull away the insulation to see but it looks glued to the chassis and is tearing. I also think it may be the loom you see in the first image towards the top-left, leading to the top of the trim cover, although tugging it doesn't get me anywhere so that may also be the wiring loom to the door.

There's lot's to take in here:


Wires appear snipped towards the passenger side door (RHD)



Wires snipped coming from the transmission tunnel



Wires look burned and snipped leading to sunroof microswitch



Two random connectors. Maybe cruise control?



Unknown connector



Another white unknown connector tucked away at the back of this loom



Snipped blue wire appears to go in to the door. There's a green one hiding inside the insulation too



Various randomly snipped wires among what look to be burned wires



What looks like a broken ground wire fell out the loom and belongs to god-knows where



Possible evidence of previous handy work


Does anyone know where the wire for the sunroof switch leads to -- or perhaps the wires are all here in the images that I need to connect and re-loom?

dnlwtsn

The broken wires were the answers hiding in plain sight! Connecting the two wires allows me to operate the sunroof! Parts are on order to recreate a new loom for this section.

To answer my own question, and to help future lurkers, the loom for the interior light and sunroof microswitch is supposed to travel from the passenger footwell up via the A pillar underneath the roof trim piece.