Yep, I documented the C-2 connector in my notes to my customer. I try to have a work plan ready for paying customers so I don't rack up a bunch of hours on random diagnostics.
The white/red wire feeds many fuses in the fuse box. My customer had another shop put in a disconnect switch due to a battery drain, so I used my ammeter to track that down. (Fix the problem, and don't use a bunch of band aids.) I traced it to that branch in the fuse box, and we removed fuses to see when the current draw ceased. That took a while because the draw would come and go somewhat randomly. Eventually I found that the passenger side door switch was wonky. There wasn't easy access to disconnect that switch, so we just pulled the fuse for now since he was not worried about the dome light or other lights on that circuit.
I'll have to look at the other circuits in C-2 to see if there are other indicators of corrosion. The terminal for the parking light circuit could have overheated at that connector. It's not like I haven't seen damage to a lot of fuse boxes and wiring for the parking lights.
The nice thing is that he is willing to get his hands dirty and does not mind providing assistance since that reduces the number of hours I charge. He seems willing to learn, too. He was thrilled that I was willing to inspect his car with him present and give him an idea of what issues he may have. What worries me, though, is that the rear brake MC reservoir was almost empty. I added fluid and bled the rear brakes, but the car is still HEAVILY biased toward the front brakes. I didn't have time to bleed at the MC, and I plan on looking at his front brakes on his next visit anyway. If it's the valve between the front and back brakes, that will be a challenge. The rubber hoses on the back need to be replaced, and I wouldn't be surprised if the front brake hoses are in the same condition. (Heck, ballooning in the rubber hoses could have caused the problems I felt in his brakes.
There are many signs of bad mechanics or idiot previous owners working on the car. It will take some money to get things right (and safe). I just want this guy to be able to enjoy his car.
Somehow I get the feeling that my retirement job will be fixing S30 electrical systems in the Atlanta area.