What was found
(CAN) AFTER GEAR RETRACTION DURING DEPARTURE THE NOSE GEAR UNSAFE ADVISORY LIGHT AND THE GEAR TRANSIT ADVISORY LIGHT REMAINED ILLUMINATED. AFTER NORMAL GEAR EXTENSION THE GREEN NOSE GEAR DOWN AND LOCKED ADVISORY LIGHT FAILED TO ILLUMINATE AND THE RED NOSE GEAR UNSAFE LIGHT REMAINED ILLUMINATED. AN ALTERNATE GEAR EXTENSION WAS PERFORMED AND RESULTED IN THREE GREEN ADVISORY LIGHTS AT THE ALTERNATE DOWNLOCK VERIFICATION SYSTEM. AS A PREVENTIVE MEASURE THE COMMANDER DECIDED TO PREPARE THE AIRCRAFT FOR AN EMERGENCY LANDING ACCORDING TO OPERATOR'S PROCEDURES. NOSE GEAR DOWNLOCK SENSOR WIRING FOUND 'OPEN'. HARNESS ASSY REPLACED.