Well it was a little cold this morning so I turned on my heat to let it warm up in my jeep. It never got warm so I cut it off and to see if it would he up as I was going down the road. But nothing it barely got warm. I was wondering what this could be.

 

Thermostat stuck open? Did you notice if it took longer for the engine temp to reach normal?

 

Mine is doing the same thing. The engine warms up fine but, just not getting the heat out into the cabin when I turn it on. Any ideas????

 

check your coolent valve on the heater core hoses, make sure its working ok, it runs on vacum

 

Don't believe '00 XJs have the vacuum operated water valve. Coolant flow is most likely blocked (heater core) somewhere. There's a slight chance the water pump could be weak.