I have a 2001 with no heat in the cab. All of the vacume doors work and there is heat in the heater hose at the fire wall, but none at the core. Seems like the core valve might be stuck. Don't know where to look for the valve. Can anyone help?

 

Ford had the valve on the trucks, took it off to save a few pennies in 97(98), then put it back because their "blend door" solution was total crap junk engineering, and caused what is happening to you. Unfortunately, they put the valve back on in 2003 I think. Just add that one to the obsolete gaskets on the 4.2 blowing engines, the 4 thread spark plugs on the 4.6 and 5.4 blowing plugs and engines (when a piece of the broken blown plug falls back into the cylinder), and the intake and exhaust manifold issues. All to save a few bucks per truck.

 

I would check to make sure the blend door actuator is moving. It is found behind the black trim piece at the bottom of the center part of dash. White box mounted to the bottom of the heater box. When changing from warm to cold you should see the shaft moving. Can also feel at the backside of the box for a 1/4 square hole, that its moving.

 

I noticed you said heater hose... Did you check both hoses? If one hose is hot and the other is cold that means your heater core is plugged. If both are hot then there's a problem with the hvac system... Blend door problem could be due to lack of vacuum to the actuator. Seen many times where the vacuum hose has fallen off