Try running the fan without the air conditioner. If you get the same symptom (fan not running) sometimes spinning the fan by hand with a stick may get it going until you stop it. Remove the shroud on top of the air conditioner and usually a sheet metal panel. Unplug from shore power before you proceed.
There are usually two capacitors. The big one has connections for fan, herm, and ground. Clean connections and try again. Should be slip spade connections. Take a picture or write down a diagram for which wire goes where. Test capacitors with a meter. They are labeled on the side for micro farads. Good multimeter needed that has this feature. Some are riveted spade connections on top of the capacitor and these can become loose also like mine was! Soldering the spade male connector on top of the capacitor to the rivet may fix if found loose and the cap tests good. Otherwise replace capacitors with new one at a time and retest.
I bought a spare 15 years ago and have not had to use it yet but I got it!
1998 2500 Dodge V10 3.55 Quad cab. Lance 5000 camper 9'10" and tow 17.5 ft Larson Boat