Ac clutch on envoy does't stay engaged - 2003 GMC Envoy

Probably an AC compressor problem - if it is even partially seized, when the AC clutch engages that will stall the truck.

Unplug the power lead from the AC compressor.If it stays locked up it a mechanical issue with the new Clutch. If it unlocks check the following. Look at the AC Relay. If it has fused or failed in the closed position the ac clutch will remain engaged. As I don't have the vehicle details I can't provide further details

You are either low or out of Freon.
The cars sensors is telling the motor it's not cold enough so it's staying on which can burn out the bearings if not taken care of ASAP.

on the Ac system is a low pressure switch ,sounds like its faulty so fit a pull or flick switch from ignition supply and run this direct to the pump

You replaced the ac compressor, and the clutch stays on, but the compressor does not run ???
Not sure I am following your info here.
If the ac clutch stays engaged the compressor should be running. You should have one hot and one cold ac line and the radiator fan should be running.

Yes. When you turn on the compressor via clutch Suction line pressures at around 3000 rpm should be around 30 PSI. If pressure stays high it is because the compressor is running but it is not doing squat and needs replacement - bad reed valves.

AC will not run unless the clutch is energized. You got it to engage by jumping power line. Check to see if there is a relay in the circuit that gets power to the clutch. 35PSI at 3000 rpm at 75 degrees ambient is about right. How about checking the AC on/off switch? Get a schematic and chech any component in the power trail to the clutch.

you need to have the freon level or pressure checked first

Fan clutches for Envoys and Trailblazer are a problem, they go out all the time.

However, it is normal for it to do this when cold, but will only stay engaged for maybe 15 seconds AFTER you've put it in gear and have started to drive. After this, it will disengage and allow the engine to warm up faster.

If you haven't already replaced the fan clutch once, you're lucky. 2002 is especially bad for the clutches, but all years don't last long. Mine lasted 90k which is pretty long.

You mean fan clutch? If so, check the wiring harness for frayed wires. These fan clutches for Envoys and Trailblazers tend to go out often. BUT, the more common problem is for the fan clutch to stay engaged, keeping the engine temperature too cool.

On another note, if you think 210 degrees is too high.....that's what it's supposed to run at, these engines run hot and should be dead on 210.