Originally Posted by ford norseman

I spent a few years as a mopar dealer mechanic, and this problem was common on the caravans. If the resistor was replaced and then went bad a few weeks later, it was always the blower motor causing the problem. If the blower motor is drawing too much current it will burn out the resistor repeatedly.
Obviously your truck is not a caravan, but the setup for these hvac systems is all pretty similar. Just my two cents, hope it helps.

Originally Posted by tbones

Finally figured out how to get the motor out. It was pretty rusted. Didn't move freely if you spin slow. Replaced motor and resistor. Back in business.

Originally Posted by jasonsbytes

Well, I replaced my resistor and the problem is still the same:

speed 1 works
speed 2 works
speed 3 (stays the same as 2)
speed 4 works

any thoughts?