What was found
PILOT REPORTED HOT RT NONESSENTIAL BUS CB PANEL & BURNING SMELL. ACFT LANDED AT DESTINATION WITHOUT INCIDENT. FOUND THAT THE RT NONESSENTIAL BUS CB OVERLAY LIGHTING PANEL WAS DAMAGED DUE TO WATER INGRESS, WHICH CAUSED ELEC SHORTING IN THE LIGHTING CIRCUITS. NO ISSUES WERE REPORTED WHEN THE ASSOCIATED DIMMER CONTROLS WERE SET TO THE OFF POSITION. WATER INGRESS DUE TO SUSPECTED WINDSHIELD LEAK.