I would start over with testing... You say the thermostat works, the water is hot, the heater core is not plugged, the hoses are hot, the fan works, and the damper door opens to the heater core 100%.......... something has been missed. Also you can pull the wire off the air conditioner compressor so it will not run and cool the air inside the duct before the heater core. Might be time to get a temp gun and get real values of the water temp, air temp in, air temp out, etc.......... your missing something.

 

My temperature gauge reads normal. Both hoses going in and coming out of firewall are both equally hot. I ran my garden hose through the heater core and flow was good. The fan is blowing strong. I removed the blend door, inspected the gears inside, they all looked good. With the actuator connected to power I adjusted the heat temp. I white gear coming out of the actuator moved as it should. Whether the blend door inside is moving, I'm not positive, I can't see it. Is there anyway to verify this? I left the whole dash apart awaiting for my next move. As much as I hate the thought of taking it to the dealer, I'm starting to think this is what I should do. Any more input would be much appreciated.

 

I would think you could stroke the blend door by hand from open to close. It only moves about 90 degrees or so. I would think you would feel a drastic difference in output temp as you moved the door manually.. If not, and you have good air flow then the heater core is not transferring heat... Possibly something like half full of lime where you get no flow or heat transfer, but can get water flowing thru the top 1/3 or half the core, but not enough fins to transfer the heat ????????

 

I have to take off the blend door motor off in the summer so the AC works and put it on when it gets cold. This is the second motor I have installed. The original had stripped gears. The new Ford part worked for about a year then stripped this last one worked less than a year but no stripped gears. On Every part the electric motor still worked. The motor goes to the hot setting and dosent automatically stop. When you turn the **** to cool nothing. The blend door itself opens and closes fine with no binding. These motors are crap, the printed circuit board in the module anyway!
Save your receipts from ford and return the part before the part warranty is up and just keep swapping them out. Or sell the explorer

 

I've encountered a couple of the motors with stripped gears, everything else still worked. So that encouraged me to make one of the first projects for the new 3D printer to make replacement gears out of ABS plastic for these. So far, so good.

-Rod

 

Steve - How do you "Stroke the blend door by hand"?

 

I'm willing to bet it's a malfunction with the printed circuit board in the actuator.
My wife's son who is a Ford Master Tech said all you can do is keep replacing the Blend door actuator.