What was found
ORD FLT 5935 THE CREW REPORTED A LANDING GEAR AIR/GROUND FAIL MESSAGE AFTER TAKEOFF. THEY WERE UNABLE TO RETRACT GEAR. THE AIRCRAFT RETURNED TO ORD AND LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED THE NR 2 NOSE GEAR DOWN LOCK PROXIMITY SWITCH. ALSO CLEANED THE NOSE WOW PROXIMITY SWITCH. OPERATIONAL CHECKS WERE GOOD. THE NEXT FLIGHT 5876 THE AIRCRAFT RECEIVED ANOTHER AIR/GROUND FAIL ON CLIMB. THE AIRCRAFT FERRIED TO CLE WHERE MAINTENANCE REPLACED THE NOSE GEAR WOW HARNESS. ALSO REPLACED THE NOSE GEAR WOW PROXIMITY SWITCH AND SERVICED THE NOSE STRUT. OPERATIONAL CHECKS WERE GOOD.