Over the last few days I have read several threads about heaters not working and blend door replacement. My '02 4.6 F-150 has 250k+ miles and I've always done regular maintenance on it. With the cold front moving in I've noticed that the heater is not blowing hot air. I flushed the radiator and flushed the heater core several times to make sure the core was not clogged. I also replaced the upper radiator hose because of the "crunchy" sound when squeezed. I also replaced the thermostat. Still the heater is not blowing hot.
I assume like many others that the blend door needs to be replaced. My question is do I need to replace the door only or the door and the motor (actuator)? I guess I need to test the motor before buying a new one.
I saw a video where you remove all the components on the transmission hump and can actually stick you finger in the motor opening to see if the shaft has come apart.
Am I on the right track here?

 

Check the coolant inlet and outlet hoses for the heater core under the hood. If both are hot, then the problem is related to the blend door, either a stripped ****, bad actuator, or busted door.

 

Yeah both lines are hot. I flushed the core just in case and it was clean.
How do I check just the actuator to see if that's the problem or if the door itself is the problem?

 

Dismount the actuator and test it for proper motion when the **** is moved.

 

If that checks out OK, it may be the bottom slot on the blend door is cracked. The only way to get at that is to pull the dash. I would think if you had the actuator off that you could stick something up into the bottom pivot on the blend door and open it up. At least you would have heat then.

 

I pulled the actuator last night and found that it didn't turn when moving the ****. The shaft looks to be in good shape with no cracks and I could turn it by hand to make the heater work.
Gonna replace the actuator tonight.

 

That could be due to a bad actuator, a bad control, or a lack of power (blown fuse).

 

I checked the fuse before I did anything else and even put another good fuse in just to double check. I also pulled the control panel for the a/c to make sure all of the connections where good.
I'm curious about the temperature control **** itself though. It has a screw in the back of it so that just that switch can be replaced. I guess I'll find out when I hook the new actuator to it.

 

....Almost got it.