I'm taking out my factory engine wiring harness and I traced the grey wire from the MAP sensor back to a loom that goes inside the car..

Any ideas where it goes and what it does?

not too bad of a job though.. that's the only wire that has me confused

thanks
...Brady

 

Props to shoebox!

It's a 5 volt reference that gets tied to several sensors around the engine compartment. (GM color coded this one)

The one you chased down probably goes into the a/c for the temp sensor.

http://csce.uark.edu/~jgbertr/rb/1995_pcm1.jpg