First time I have ever had this problem with a Ford. The heat on my 2001 S-Crew is just mediocre at best. Even with the temp setting on high and the fan kicking, it just won't keep the truck warm. Operating temp is fine, coolant is full, etc. The air cranking out of the vent is even hot- it just doesn't warm the truck up. My feet are roasting but my hands are frozen. Can I get the heat out of the plenum box any place other than right on my right foot? Like out the middle?

I also see the two vents under the seats that go to the back seats. Are they there for looks? I can't feel anything coming out of them. My kids hate this truck- they freeze as well.

My '88 Taurus, my '89 Ranger and my '96 Taurus all rocked when it came to the heat. In fact, my Ranger was the best vehicle I have ever driven- the heat was warm, even and easily controlled. This S-Crew is like tinkering with a finicky woman- you have to get it JUST right for it to perform.

I thought an '01 truck would be far ahead of an '89. Guess not.

UFM82

 

have you tried setting the selector to the vent position or floor/vent for this?

 

After you have shut the truck off move your Mode Selector Switch to various positions and see if you can hear the click & thump of the pleneum changing positions with it. I have read on here that these vehicles are known for trying to open or close it to far resulting in it wedging in one position or the other. If this is fine then check ducts for obstructions and that they are all connected. This year it has not gotten below 10 Degrees here so far, but mine is working great! After about 10 mins of the truck warming up, I have to turn the TCK down to just over 1/2 and with the fan on lowest...It still roast us out! Hope you find the problem..Good luck!