The AC systen on my truck will not engage the clutch. The system is fully pressurized. Last week I took it to an AC repair house and they replaced the AC control module on the dash. Two weeks later it will not enable the clutch again. I can force the clutch buy pulling one side of the relay coil to ground. I also tried shorting the pressure switch, but the sytem will not start. Does anyone have a chevy schematic for the AC control circuit. I have a Haynes, but it is not very detailed.