2000 Silverado 4.8 AC compressor never stops

[bwood]

I reread your last post and see 25-30psi at idle. What was the approx outside air temp when you took those readings? Also you say it climbed to 60-70psi, I'm thinking 70 is getting pretty high for an idle system (compressor off). It might be worth it like Truckdude said and pay a shop (use someone that specializes in AC work), and pay them to diagnose it. It would probably be cheaper than buying a set of guages (70-100bucks). Just have them check pressures and recommend a solution, and have them price the solution. Don't take the "you need a whole new system crap". Next time you think about it have someone rev it up and down and watch the compressor and see if the clutch is going on and off.