I have a 2001 F150 with a heating problem when I put the heating control to floor it blow's very little on floor and 80% to the defrost, this also happens with the panel/floor heating position. I did some basic checkes and not sure where else to go, any help would be appriciated.
Thanks

 

Sounds like either a diverter is hung up or binding, or the actuator is not working. It helps to have a shop manual to show the layout and the various actuators - rather difficult to describe in words.

 

Do they still use the vacumn lines for this as they use to???

 

on my 2000 i still have vac lines for the zone control.

 

I had that problem on my last Chevy truck... A rubber line came loose and I had no control of heat distribution, as it came out of most everywhere... My 68 Buick was corroded up and once I took it apart and cleaned and lubricated it has worked fine. My work in progress…
It might be worth crawling under there and giving it a good once over for a disconnected rubber line of a cracked one. Especially if you have been under there lately doing some work.