Im an auto body tech and Im stumped by this one. 1996 Jeep Cherokee Sport 4.0L Automatic w/AC. Started a year ago or so slowly, the jeep lost its ability to produce any hot air in the passenger compartment. Blows cold air just fine, no a/c though (the compressor is junk), Ive replaced the thermostat recently, the water pump recently (not because of this problem), blend door operation is fine, heater hoses in engine compartment get hot as they should, replaced the controls on the dash, took a garden hose the heater hoses to check for a clog (there wasnt), checked all of the fuses and relays, replaced the heater hose 4-way spliter in the engine compartment, the coolant temp sits at normal temp, and also flushed and replaced coolant. Nothing seems to be wrong so im stumped as to why im not getting any heat. Im an I-car certified tech and have been doing this for a long time so only answer if you know what your talking about, thanks!