The AC in my 2001 Chevy is not cooling. I put my gauges on it and it has 135psi static pressure at 90 degrees outdoor temperature. When the compressor is engaged the low side is 30-40psi and the high side climbed to 400psi before I shut off the system. I assume the high pressure switch is not working, but this does not explain why the system is not cooling.
I have already replaced the orifice tube and accumulator.
What the hell is going on?

 

Did you pull a good vacuum and purge the manifold gauge hoses?

 

Yes, I pulled 28 inches of mercury and held it for 30 minutes before I recharged the system. I keep my high and low pressure lines on my gauges pressurized and I purged the fill line before I added refrigerant.

 

Are you sure that it is a refrigeration problem, and not a problem with the air doors inside the cab?

 

First off the high pressure switch will not turn off the compressor until the high side pressure exceeds 420 psi. I attached a diagnostic sheet for the AC system when the low pressure is within spec and the high side pressure is too high.