Abstract: The conventional sun visor of a vehicle is provided with a fan system including a heater for defrosting and defogging the vehicle windshield. The fan system includes a fan subassembly body mounted in an opening in the sun visor by a retainer subassembly including first and second retainer frames having flanges insertable into the fan subassembly body for securing it in the visor opening. First and second grills are mounted over the faces of the subassembly body by mechanical fasteners which extend through the body and retainer frames. An electric heating element is mounted on at least one of the grills for heating the airstream geneated by the fan of the fan subassembly. The fan and heating element are selectively powered by the vehicle electrical system through an on-off switch.