I have a 95 f-250 and the heater doesn't blow. It gets a little air but that air is hot. It seems like it is stuck on low. I was wandering if it is controled by vacume presure or by electrical? it isnt lke the old ones where it is done manualy from a long peice of metal is it? I have little plugin heaters from my house that i riged to the battery but i really want to get this fixed before it really gets cold.
Dan

 

The heater might not blow, but your vacuum sucks. There is one common problem with the vacuum, the white plastic line that runs thru the firewall near the top passenger side of the engine bay tends to rot out and leak. If I recall correctly, that is for the blend door controller. But when the blend door doesn't move right, you tend to get good air movement but the air is warm (i.e. not HOT or COLD) when either the A/c is on or the heat is on. If you are not getting any air movement you may need a new fan motor, or fan motor resistor.
The easiest thing to troubleshoot is the condition of the resisitor..it is mounted on the front of the plastic blower case( in the engine bay) with two screws, and has an electrical plug running to it. Unplug the harness, pop out the screws, and ohm out the resisitors, they are just metal coils, usually, you can see the open circuit if they are bad.

BE very careful when handling any Ford plastic vacuum lines, they are brittle and will break even if you are trying to be careful, anotherwards, they suck!

 

Thanks I will try that It used to have good heat then it sat for 2 years with out being run so could something like mice move in there? Or is it a closed unit other than the vents that heat or cool?
Dan