As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED THAT THEY RECEIVED A LG AIR & GND FAIL MSG IN FLIGHT. THE CREW RETURNED TO FIELD & LANDED WITHOUT INCIDENT. FOUND THE NLG WEIGHT ON WHEELS SWITCH TO BE FAULTY. THE SWITCH WAS SWAPPED WITH THE LT MLG DOWNLOCK PROXIMITY SWITCH & DEFERRED. THE DEFERRAL WAS CLEARED ON 4/25/2014 WHEN MX REPLACED THE LT MLG PROXIMITY SWITCH. OPERATIONAL CHECKS WERE GOOD WITH NO FURTHER DEFECTS NOTED.