Wiring Questions and Mystery Connectors


Well-Known Member
Hi all,

Getting pretty close here to first start and I'm finishing up some electrical work on the body harness and grounds and have a few questions:

***A few relavent details***
-Donor is 2007 SS/SC but has been turbo swapped to Z54
-Wiring harness was done by DF

1. I believe this was from the MAP sensor on the supercharger. What becomes of this now that there is a turbo in it's place?

2. Does anyone know what this connector goes to? Really not sure on this one

3. So as mentioned, DF did my harness and used this tan wire to extend the radiator fan wire. However, in the video (part 20 I think it is), where the fusebox installation is covered, Lonny mentions soldering this to a light blue wire from the black multi-plug - The light blue wire in my black multi-plug is still intact. I'm pretty sure I just need to cut this and then solder in the tan wire. Can anyone confirm?

4. This pops out right over the transmission housing, next to the EVAP solenoid connector. Does anyone know what this goes to?

5. This ground pops out of the main harness right at the fusebox. Where should I ground this?

6. In @Adam's First stage assembly post, he mentions the tunnel as one of the places that should have something grounded to it. I do not recall seeing any ground studs inside of the tunnel before I sealed it up (or on the outside of the



Well-Known Member
5. My transmission mount has a ground lug. Under the fusebox.
6.the tunnel ground was eliminated.
So Ross in regards to #5...How would you accurately determine whether or not something should be grounded to the chassis vs the powertrain? Does it matter?


Goblin Guru
Not to put too fine a point on it, ground everything to everything else, unless it is not supposed to be grounded! Especially a big, thick ground from the frame to the engine somewhere near the starter! Two wouldn’t hurt but someone might think that is silly. I’ve personally fixed several cars with an engine to body and frame ground. Two had computer “malfunction”! Corrosion growing from the neg battery clamp and up under the insulation causing excessive resistance at all grounds, what a mystery! I stripped back the insulation when I noticed the plastic insulation was very lumpy and a little crunchy. The corrosion had grown down the copper plated aluminum wire several inches, all inside the insulation! ( A personal preference is that all battery cables be stranded, real copper elements! Thickerer the betterer! That copper plated Aluminum stuff does ok until the end of the warranty?)This corrosion is never caused by excessive battery maintenance!


Goblin Guru
I tied all of my grounds together just to be safe. I also put a ground block by the brake booster so I could have easily accessible and confident ground terminals for accessories. It also keeps ground lugs from getting crowded.


Well-Known Member
Awesome thanks guys - Really appreciate the help. I got that last ground tied off last night. Now just need to pull the tune, send it to ZZP, figure out what to do about exhaust, and figure out how a return style fuel system works:D and then I should be ready to crank her. All in a day's work righto_O