Peterbilt 379 no ac

Hello. Im posting this to maybe help someone with a similar problem. My 1999 379 had no power to the ac compressor clutch when I bought the truck. I checked the system and found that I had no ground to one side of the clutch relay. I found a schematic of the system and started checking wires. The fault was in a connector that brings the hi/low pressure switch wires into the main harness. The connector was a square gray connector to the left of the main harness. The ground wire from the pressure switches is number 495A. It was broken inside the connector. It was repaired and now works great. The output side of the connector turns into wire 570 in the main harness. If you have a ground problem, try checking these wires. I hope this helps someone.