WHILE DRIVING, SMOKE IN PASSENGER COMPARTMENT, NO INTERIOR LIGHTS OR RADIO. LATER DISCOVERED NO STOP LIGHTS OR RUNNING LIGHTS. REPLACED HEADLIGHT SWITCH AND UNDERDASH FUSES. HEADLIGHT SWITCH BURNED AND BROKEN, VEHICLE HEADLIGHT WIRE HARNESS MELTED NEAR ONE CONNECTOR. FORD SERVICE SHOP HAD TO REPLACE HEADLIGHT SWITCH TWICE BECAUSE OF FIRST REPLACEMENT DIMMER RHEOSTAT FAILURE.