My heat doesnt work, blows cold air, AC works great, blower works great. I
changed the thermostat housing and the heater control valve. Coolant levels
are fine, no leaks
The temperature blend door is probably stuck on cold. U will probably need a blend door actuator or the door it self if it’s broken
Actuator failure is common among explorers. And they are not located in an easy to get to location. Normally when they are about to go out you hear a clicking noise when the knob is turned from hot to cold, but not always. There are some work arounds on the net involving drilling a small hole in the dash and hooking a piece of wire around the actuator rod to pull the door closed after the engine starts. Look for the video.