As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ORD FLT 6062 ON TAKEOFF CREW GOT AN AIR GROUND WARNING, AND THE GEAR WOULD NOT COME UP. RETURNED TO ORD AND LANDED WITHOUT INCIDENT. MAINTENANCE INSPECTED AND REPLACED THE NOSE LANDING GEAR WEIGHT ON WHEELS PROXIMITY SWITCH. ALL OPERATIONAL CHECKS WERE GOOD. AIRCRAFT RETURNED TO SERVICE.