I have a 1999 Chevy Silverado with a 5.3L engine with 150,000 miles on it. After the engine has been running a while, the AC kicks off. The fan / blower is still working, and the AC light is on next to the AC button on the dashboard, but there is no cold air. I can turn off the AC switch on the dash and wait about 30 seconds and turn it back on and I have ice cold air blowing out. It will work for 5 to 10 minutes, then it goes out again.

I have checked the coolant / refrigerant lever and it is ok. I have also replaced the low pressure sensor switch on the evaporator core. I was about to replace the high pressure sensor switch, but wondered if anyone had any suggestions. The switches are about $15 each, so it is not bad but the try and replace method can add up after a while. Anyone else had this happen, any thoughts.

Thanks