What was found
PILOT WAS PERFORMING GND RUN FOR ENG COMPRESSOR WASH, PILOT NOTICED SOME SMOKE FROM PEDESTAL SWITCH AREA & A BURNING SMELL, BLUE LIGHTS ON FUEL PUMP, TAXI & LANDING LIGHTS FLICKERED ACCORDING TO THE PILOT. ACFT WAS SHUT DOWN & DISCONNECTED THE BATTERY. REMOVED COVER FROM ALPHA 30 PANEL & NOTICED A MORE BURNED SMELL WHEN COVER WAS REMOVED. REMOVED PEDESTAL SWITCHES ONE AT A TIME & FOUND THE AVIONICS SWITCH BASE BURNED & 2 PINS APPEARED TO STAY IN THE CIRCUIT BOARD AS WELL WHEN THE SWITCH WAS REMOVED. THE CIRCUIT BOARD UNDER THE AVIONICS SWITCH BURNED AS WELL. REPLACED ALPHA 30 PANEL & AVIONICS SWITCH. POWERED UP ACFT & GND RUN PERFORMED NO DEFECTS NOTED.