I've had an '01 cherokee for a few years now, but until last summer, I've never had working AC in the car. Last summer, I had the system checked and recharged, and the HVAC system worked flawlessly until the heater core blew out around October. I had that replaced with everything continuing to work as usual. Throughout the winter, my heater would work well, but the air seemed to come out at the highest temperature setting (didn't bother me at the time). As it started to get warmer, I tested out the AC to make sure it would function correctly, but the air would still come out at the highest temp, no matter where I moved the temp dial. The compressor would start up and function as normal, and the air coming out of the vents would be cool when starting cold, but once the engine started to warm up, the air would heat up. When i took the truck to a shop where my friend works to replace a blown brake line, I had them recharge the AC and check the whole system, and no one at the shop could find anything wrong with the components (everything was functioning correctly). At first, I thought there may be a problem with the temp control switch, but after searching across the web and many forums, I came across the blend door issue in these Jeeps. Would the blend door being stuck fully open cause this issue, or could there be another underlying issue causing this?

 

The Blend Air Door stuck at full heat could be the problem.


You can check to see if it's working.


Position yourself in the passenger footwell so you can look up to the corner near the floor outlet. You'll see the actuator on the bottom of the HVAC Unit.


With the ignition switch to RUN, engine off. Turn the temp control **** full heat to full cold - slowly. You should see the white extension on the bottom of the actuator slowly turn.


If it doesn't turn, you'll have to remove the actuator assembly and leave the electrical connector hooked up and try it again. If it still doesn't turn, the actuator motor is probably smoked. If it does turn, there's a possibility the Blend Air Door is jammed. See if you can turn it with your fingers or with some pliers. If it won't move it's jammed.


If the actuator turns properly when installed you have other issues.


If fuse F25 in the diagram is blown the blower would not work.




.

 

I checked the actuator, and it's turning. Does this indicate blend door issues or something worse? I've searched the internet for blend door fixes, etc., but have mostly found tutorials and info on Grand Cherokees and very little on XJ's.

 

Remove the actuator assembly.


See if the intermediate drive shaft (white thingy) is wallered out.


If it is, try to turn the blend door with your fingers and if it won't move, use some pliers to try and make it move.

 

You need to do two things:

1. Check to see if there's a politician hiding in your system. That's the #1 cause of hot air problems.
2. Learn to use the "Reply" button instead of the "Quote" button.

 

1. There were some people hiding there, but they ran off before I could identify them...

2. I will take your great advice and cherish it my whole life!

 

I removed the actuator and was able to move the door manually. It seems to have helped the AC. I've researched some more and it looks like being unable to control the temperature is indicative of blend door failure in XJ's.

 

Is the intermediate drive shaft (see post #4) damaged or is the blend-air door shaft damaged.


If the actuator works (installed) and the blend-air door moves freely, and the drive shaft and intermediate drive shaft are not damaged, I'd say there's nothing wrong with the blend-air door system.