2002 ford focus wagon

I recently wrote in about my a/c not working along with the radio`s fm frequency… i had the a/c filled with the proper refrigerant and all main components are working but the switch when turned to the higher numbers on the fan kicks the air from cold to warm…the fm frequency only is an intermitten problem sometimes after ive tryed the a/c…the dealership believes maybe a resistor or relay problem…any thoughts