2003 C4S Instrument Cluster Wiring Help

Hello, I'm hoping someone can help me troubleshoot an issue with my 2003 Porsche 911 Carrera 4S (996.2) instrument cluster. This all started because a previous owner had put a sticker over the tachometer face, and I couldn't stand looking at it anymore. I replaced the gauge face and reinstalled the cluster. During testing, I discovered that both the speedometer and tachometer stepper motors were no longer working. It appears the previous owner had pressed the needles down far too tightly onto the shafts. It took a significant amount of force to remove them, and I believe that pulling force damaged the stepper motors. While removing the cluster to replace the steppers, the green connector literally disintegrated in my hand. The gray/white connector wasn't much better, so I ordered brand-new replacement connector housings from Porsche/VW. The replacement housings did not accept the original indexing/bus inserts, so I had to repin the connectors. I have a strong mechanical and technical background, and I wouldn't have attempted this if I wasn't confident in my abilities. I transferred each wire individually, one pin at a time, verifying the pin location before moving to the next wire. I also cross-referenced every connection against photos I took before disassembly. I'm very confident the harness is pinned correctly. For the stepper motor replacement, I had an electrical engineer with over 30 years of experience perform the surface-mount soldering using the proper equipment. At that point, I expected everything to work. Unfortunately, after reassembling the cluster and reconnecting the three harness connectors, I turned the key... and absolutely nothing happened. The cluster was completely dead. I found that Fuse B1 (instrument cluster) had blown. With the cluster unplugged, I replaced the fuse and turned the key on. The fuse held. I then plugged the cluster back in and applied key-on power again. The cluster remained completely dead, but the fuse no longer blows. At this point, I see two realistic possibilities: I made a mistake while repinning one of the connectors. I think this is unlikely given how carefully I transferred and verified every wire, but it's still possible. Something went wrong during the surface-mount repair, despite the experience of the engineer who performed it. Either scenario is possible, which is why I'm trying to eliminate every variable before sending the cluster out for repair. For all I know, the cluster itself may still be perfectly fine. I opened the cluster again and inspected it for any obvious burnt components, damaged traces, or solder bridges but found nothing suspicious. I also started checking the vehicle harness with a multimeter. I found battery voltage present on the green connector with the key off. However, I suspect that the solid brown wire at pin 32 of the green connector should be the cluster's primary ground, yet I'm not seeing continuity to chassis ground when I test it. My questions are: Does anyone have a color-coded pinout for a 2003 Porsche 911 Carrera 4S (996.2) instrument cluster so I can verify every wire location? Can anyone confirm whether the solid brown wire at pin 32 of the green connector is the primary ground for the cluster? If it is the ground, is it switched or relay-controlled in any way, or should it be a permanent chassis ground regardless of key position? Without a proper ground, the cluster obviously won't function. I'm simply trying to rule out a vehicle-side wiring issue before sending the cluster out for repair. I don't want to repair or replace the cluster only to have a wiring fault in the car damage it again. Any insight or wiring information would be greatly appreciated. Thank you for your help, PDroid

I uploaded a wiring diagram when I did my manual swap. Searching on my phone is crap though. Search under my name for my swap thread, I believe the file is on the first post. It�s a pdf.

Here is a link to the entire workshop manual for the .1 and .2: https://audipages.com/911/wsm/ If you don't have ground on the large brown wire, I'm going to say that's your issue. I would just jumper the brown wire to ground with the cluster pulled after you check the wiring diagram and I'm pretty confident that it will power up. Sounds like a pretty easy fix.

Thanks for the help. I was able to get it booted up properly last night.

Do the new stepper motors operate as expected now?

Yes. Everything is working perfectly, except I gained a loose connection on the LCD clock. So I'll be removing this and checking those solder joints. Otherwise it works perfectly. The car ended up requiring a handover aka battery unplugged for a half hour. Hooked it back up and the cluster booted right up. I also suspect that the VW replacement plugs don't seat as well as the Porsche plugs. They design is slightly different from what the car originally had. I believe that when I reconnected the harness, they plugs seated better and the handover procedure was a coincidence. UPDATE: The clock was an issue with a dirty contact on the cluster from handling it. I wore gloves, but something happened. I cleaned the clock contacts, secured the clip on the screen, and everything is back to normal.