As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MCI - INFLIGHT MSP-DFW. HEADING ANNUNCIATOR ON BOTH FLIGHT MODE ANNUNCIATORS CAME ON. UNABLE TO DETERMINE WHICH SYSTEM WAS CORRECT DUE TO LARGE DEVIATIONS ON BOTH SYSTEMS COMPARED TO MAGNETIC COMPASS. FLIGHT DIVERTED MCI LANDED WITHOUT INCIDENT. REPLACED CAPTAIN AND FIRST OFFICER COMPASS INDICATORS. SYSTEM GROUND CHECKED NORMAL OPERATION.