What was found
A BURNT ODOR WAS NOTICED FOLLOWED BY SMOKE IN THE COCKPIT, COMING FROM THE TRIM INDICATOR LIGHT PANEL. THE PILOT CLOSED THE RHEOSTAT AND RETURNED TO BASE. AFTER INSPECTION OF THE LIGHT PANEL, HUMIDITY WAS FOUND UNDER THE PANEL, WHICH CAUSED A SHORT CIRCUIT. THE PANEL WAS REPLACED AND AIRCRAFT RETURNED TO SERVICE.