I have a 2004 F150 where the ac will randomly shut down after driving for a few minutes. It does not do this every time I drive it but when it does it’s very annoying and usually happens within the first 20 ish minutes of driving. Everytime this happens the compressor is off. When it was off I checked for power at the plug going to the compressor and had nothing. It’s not the fuse because it will come and go randomly. I replaced the relay for the compressor and it still does it. I checked the ac pressures when it was working and the pressure were perfect so it’s not low or overcharged. Any ideas on what it could be? Pressure switch? Thanks for any help

 

Define exactly what "shut down" actually means.

 

It blows warm because the compressor shuts off.

 

Check the compressor clutch gap for excessive gap due to wear.