I can repair almost all the appliances in our rig and in the S&B but I don't do ac, so my recommendation is if it is not in the owners manual or a maintenance manual(do an on-line search) I take it to a pro. LCI owns the name now and they are pretty good on publishing manuals so if you don't have one do a search of their publications.
Most AC squirrel fans have oil impregnated bearings and sometimes oiling will help but not always and often only for awhile. I wouldn't try tearing it apart myself, but that's just me.
