We had a problem with our dash AC. The fan would work but only on high speed. We decided to fix it before it quit all together.
We have a Monaco DP mh but I believe most are similar.
It turns out the fan switch was a Ford Part which we got at a nearby Ford Dealer. We were told it would either be the fan switch or the resistor. The fan switch is on the front passenger side of the MH, accessed through the generator compartment. It was an easy replacement, but unfortunately not the problem. Oh well, It was only a $27 part. The resistor was a little harder to locate but in the same general area. Hubby got it out and replaced and we now have all 4 dash fan speeds. I'm not sure this is your problem since you have no fan at all. I did a Google search and found our problem was quite common. Good luck.