2000 XJ heating problem

Well it's starting to get a bit colder here and i went to turn my heater on the other day..... the vehicle heats upto normal opperating temp. 100* so i turn my heater on full blast and it has a musty smell (like AC kind of, an dthe vehicle is completely dry inside so it's not musty from inside moisture) and the heat blowing from the vents is not very hot it's morelike a warm air. I have never had a vehicles ac compressor click in and out when the heater is running is this normal? I'm kind of stumped i am quite mechanicaly inclined but this one's got me. anybody out there having the same problem??

Where is here ? Normal operating temperature for a Cherokee is 210* F. The A/C compressor will turn on when you are in the Defrost position. It shouldn't be come on when you have just the heat on.

ok, that makes sense it may have been on foot and defrost. Here is British Columbia, Canada. 100*C (canadian vehicle) thanks for the reply.

What year/engine, etc.?

EDIT: Losing my mind, 2000 in the title!

So, 100C is 212F, so that is normal. Either your heater core is plugged up or your blend door isn't operating properly. 2000, etc. XJ's are kind of known for the (temp) blend door breaking. There is a kit on Ebay to hack into the housing and repair without dropping dash and HVAC unit. You've got to climb under the dash and check if the blend door actuator is working and remove that to see if you can move the door with your fingers. A while back, there was a thread where the wire from the control to the actuator went bad.

winterbeater said:

So, 100C is 212F, so that is normal. Either your heater core is plugged up or your blend door isn't operating properly. 2000, etc. XJ's are kind of known for the (temp) blend door breaking. There is a kit on Ebay to hack into the housing and repair without dropping dash and HVAC unit. You've got to climb under the dash and check if the blend door actuator is working and remove that to see if you can move the door with your fingers. A while back, there was a thread where the wire from the control to the actuator went bad.

Click to expand...

x2, there is no coolant control valve on your late model, so the heater core and/or the blend door are suspect.