98 Explorer heater

I just purchased a 98 Explorer and I am trying to figure out why the heat is always on. I replaced the temp control switch on the climate control panel but no luck. It does cool on the Max A/c position. I,ve seen a lot of "no heat" posts but mine is all heat, related?. Thanks

Probably related. Sounds like a blend door that is not switching. Either the door is broken or the actuator had quit.