What was found
(CAN) LANDING GEAR FAILURE: WHEN SELECTING GEAR UP WE GOT 3 RED PLUS 3 GREEN, GEARHANDLE AMBER LIGHTS AND THE GEAR STAYED DOWN. STOPED CLIMB AT 3000 FT TO CONSULT QRH AND CREW BULLENTINS. AFTER APP. 5 MINUTES THE GEAR RETRACTED WITHOUT ANY INPUT FROM OUR SIDE. GEAR DOWN BEFORE LANDING WAS OK. INVESTIGATION/ACTION: DURING TROUBLESHOOTING THE NOSE WHEEL CENTERING SENSOR WIRE WAS FOUND BROKEN. NOSE WHEEL CENTERING SENSOR HARNESS REPLACED. LANDING GEAR RETRACTION/EXTENSION CHECKED ACCORDING AMM 32-31-00-710-801. THE GEAR UP SELECTION FAILURE WAS CAUSED BY THE DAMAGED NOSE WHEEL CENTERING SENSOR WIRES.