What was found
DURING CRUISE PILOT NOTICED LOW VOLTAGE LIGHT STARTED TO FLICKER. AT THE SAME TIME PITOT HEAT AND NAV LIGHT BREAKERS TRIPPED ACCOMPANIED BY A MELTED PLASTIC SMELL IN CABIN. PILOT MADE A SUCCESSFUL LANDING AT INTENDED AIRPORT. MAINTENANCE INSPECTED THE PITOT HEAT AND NAV LIGHT CIRCUITS/WIRING AND ASSOCIATED COMPONENTS. BOTH THE PITOT HEAT AND NAV LIGHT SWITCHES WERE REPLACED AS A PRECAUTIONARY MEASURE. THE POST LIGHT WERE FOUND TO BE INOPERATIVE AND WERE DEFFERED IAW MEL PROCEDURES. POST MAINTENANCE GROUND RUN AND OPERATIONAL CHECK FLIGHT WERE BOTH SUCCESSFUL. AIRCRAFT HAS BEEN RELOCATED TO THE MAIN MAINTENANCE BASE FOR MORE THOROUGH INVESTIGATION INTO THIS OCCURRENCE.