My heater blows only cool air, even at operating temp. I turned the ac on for a few seconds, then back to heat and is helped for a few minutes but cooled off again. I changed the radiator not long ago and flushed.. didn' t seam top help much either. Also if it was the h-core would it be leaking?
could be the heater control valve, check it under the hood to see if the vaccum line came off or cracked. The heater should still work if the core is leaking, checked the fluid level latly? Do you hear the vents opperating when you adjust the vent style(head/feet/defrost)?
Could be an actuator. I think there are several technical service bulletins for the Heating/ac system on your year of jeep. My 02 has a similar problem that I found on the TSB's and am going to check mine out tomarrow.
Sounds to me more like either your water pump or thermostat might be bad. The problem you describe is usually what happens when one of the 2 go (your engine heats up but since no fluid circulates through the engine and heater core you don't get heat inside the vehicle.) probably the only reason you get heat for a little bit whenn you turn it off then back on is the fluid in the hoses will still warm up a little from just the heat under the hood, but when you turn it back on the fan cools it down real fast since it wouldn't be near as hot as normal. I would start by replacing the thermostat first if you supect this to be your problem or both at the same time. takes about a hour for someone mechanically skilled probably 2 for a newbie.
There is someone in my head but it's not me
01 TJ SPORT,d44 w/true-trac in rear, 4 in. lift, 33's
Fixed mine the day I previously posted but was watching it to make sure. The problem ended up being the check valve on the line next to the manifold. Unless you have already done this you might want to verify if the vent door/actuator arm for the hot and cold setting is even moving when adjusted. vacum problems is a good place to start, that one leaking check valve was causing my system to do some strange stuff.