How do you rechage the air conditioner in the Sleeper of 2001 379?

Begin with pictures from YOUR end?

Make and model year will also be helpful.

My truck for instance has a refrigerant line switch that cuts the refrigerant from the sleeper based on the sleeper thermostat, in your shoes, thats the first place i would look, but dont know if thats how yours is set up

 

Truck front and rear AC are one system. You have bad clogged valve on rear or stuck in heat position blend door. Check with your hand if rear evaporator is cold.

 

I’m guessing you have the water valves turned off on engine. That rules out hot coolant cancelling out the A/C. Probably the expansion valve, or orifice. Whichever KW has. Just a guess. Maybe the temp control valve. Not sure about KW, but temp valve and temp control switch. Temp control probe in evaporator if equipped. Gotta be one of those. If it has a temp probe, you can hear it click on and off when working with the temp dial.