So I drive a 2000 Jeep Cherokee Sport.

The problem I'm having is with air conditioning. My heater core works great as normal and heated my car no problem over the winter. Now it's almost summer and I started using my A/C system for the first time. It was low on freon so I filled her up to the correct pressures and it works great. But only when I use my manual heater core shutoff valve. It blows cold air with the heater core disabled but not when coolant is flowing through it. So if I want heat I have to open the valve, and if I want A/C I have to close it. My shut off valve is aftermarket so my questions are...

1. How do stock Cherokees blow cold air with no heater core shut off valve?
2. Is my cooling system under producing? It's cold with the valve closed, but it should be able to override it's own heat, right?
3. Or is there a broken component in my HVAC system which is supposed to block the heater core from letting the A/C pass through it?


Also my compressor is working great, doesn't slip, or anything, always is engaged like it should be

 

What heater core shut off valve? The 2000 XJ isn't supposed to have one of these.


It sounds like you have a Blend-Air Door issue. Door stuck or its actuator is inop.


Here's a schematic of the Blend-Air Door system.





If you climb in the passenger foot well and look up in the left corner, under the HVAC Unit, you'll see the actuator.


Turn the ignition key to RUN (don't start the engine) and turn the temp control **** on the climate control panel from stop-to-stop. You should be able to see the intermediate drive shaft turning. If it doesn't turn, remove the actuator and leave the connector hooked up. Try it again. If the actuator does not turn it's probably inop. If it does turn, attempt to turn the Blend-Air Door actuator. If it won't turn, it's jammed.