I was in the midst of doing valve seals on my 87 iroc 5.7 tpi this weekend when I had to move the AC compressor to get the driver side valve cover off. At that time, I found the wiring harness leading to the AC compressor had 2 of 3 connectors disconnected. The AC compressor was connected but it appeared that the driver side temp was unplugged and there was one additional plug that was not plugged in anywhere. It looks like its been unplugged for some time and I cant figure out where it goes. Any help? Its one of the three plugs that is on the end of the stock harness leading back from the AC compressor....

 

Took a pic of the harness last night. Looks like one for sure is the temp sending unit from driver side, the other I am not sure of...

 

 

Second pic looks like the one that connect to the AC unit

 

In the first pic on the lower left you may make out that the AC compressor is plugged to one of the three ends of that harness. Does the AC compressor have 2 connections?

 

Opposite of yours, but notice that plug at the TOP of the AC

 

got it, must be an electronic connection for the clutch to engage/cycle the compressor?

 

YES, the one in your pics is a pressure switch, my pic shows the power. If you unwrap the crappy GM tape job, you'll see they have a diode in there

 

Great! Thanks that solves it. You are right on. I noticed the diode. Thanks

 

You bet!