What was found
(CAN) A 1900 D LANDED AT A MX BASE WITH 3 ELECTRICAL SNAGS. CABIN LIGHTS WOULD INTERMITTENTLY CHANGE FROM PARTIAL TO FULL. ON LANDING, GROUND FINE SELENOIDS WERE CHANGING FROM FLT MODE TO GROUND MODE AND STEERING DISCONNECT ACTUATOR CYCLED FROM GROUND TO FLT MODES NUMEROUS TIMES. IN DEPTH INVEST REVEALED THAT WIRING OF CABIN & READING LIGHTS WAS NOT IN ACCORDANCE WITH WIRING MANUAL. IT APPEARS FROM MANUFACTURE, THE POSITIVE LEAD WAS NOT ALWAYS INSTALLED ON HOT SIDE OF BULBS. GENERAL FEELING IS THAT THE ELECTRICAL BUSS WAS BEING BACKFED 28VDC. THE LIGHTING SYSTEM WAS REWIRED IAW THE WIRING MANUAL AND ALL THREE SYSTEMS FUNCTIONED NORMALLY. A FLEET WIDE INSPECTION AND RECTIFICATION OF THE WIRING IS IN PROGRESS.