Earlier today I switched on my defroster and changed the temperature heat up. Since I did that I am no longer able to adjust my temperature of air conditioner, it just blows hot.

Any suggestions?

 

Check your heater control valve see if it is stuck open or if the vac line came off, or you can check the cabe that is connected to the back of the temp control slider to see if it came loose. And check the Vac lines on the back of the heater/a/c contrer. That's what I would suggest but I could be wrong

 

Sorry, I was in a hurry earlier and now realize that I need to clarify further. I have a 2001 Cherokee Sport 4dr 4wd with the 4.0 and auto. I just got done checking the actual rotary temperature dial (electronic) and its resistance did vary, so it should be good. Everything changes between defrost, vent and floor like it should. When switched to A/C the compressor kicks on and the lines get frosty cold just like they should. I looked at the vacuum ball and it appears to be ok, I traced the line all the way back to the manifold and it looks fine. The recirculate door functions as it should as well.

So...what the heck controls the dang temperature, where is it? What does it look like? How do I check it?

Thank you very much!

 

Where is the heater control valve?

Dont have a cable.

Checked the vac lines on the back of the heater/ac contoller...that all looks fine.

 

sorry my information only applies to 96 and older XJs

 

As of yesterday, I'm having the same issue with my '01 Cherokee Sport.

Can anyone shed any light on a possible troubleshooting route for this model year?

 

Under the hood the smaller heater hoses converge on the heater control valve. On my 90 it's controlled with vacuum, you can see the lever move when the control lever is moved...has a diaphragm with a small hose to it.