The resistor will run quite hot, which is why it is located in the airstream of the HVAC system. When only position 4 works, it suggests the resistor pack is bad. When position 4 works, and some of the other positions do not, it suggests a problem with the blower switch.
Thanks, I will go that direction. The confusing thing is that the thermal fuse went on the new resistor. Luckily I found an equivalent? at Radio Shack for $1.69, rated for 142 C or 288 f, same color scheme as the one from Ford. I am about to try it again.