What was found
(CAN) AFTER TAKEOFF CREW WAS UNABLE TO RETRACT THE ACFT LANDING GEAR. THE CREW ELECTED TO RETURN TO AIRPORT OF ORIGIN AND CONTACT MX. THE ACFT WAS FERRIED HOME WITH THE GEAR DOWN. UPON INSP FROM MX, THE MLG SAFETY SWITCH WHICH CONTROLS THE AIR/GROUND PORTION OF THE LANDING CONTROL SYS WAS FOUND TO BE INOPERATIVE. MX CHANGED THE SWITCH AND THE GEAR FUNCTIONED CHECKED SERVICEABLE. TOTAL TIME ON THE SWITCH COULD NOT BE DETERMINED.