As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DFW INFLIGHT T2421/29APR - CREW REPORTED RIGHT NUMBER TWO FIRE LOOP INDICATION ON CLIMB-OUT. RETURNED TO DFW AND LANDED WITHOUT INCIDENT. FOUND LOWER FORWARD FIRE DETECTOR OPEN. REPLACED LOWER FORWARD FIRE DETECTOR. SYSTEM GROUND CHECKED NORMAL OPERATION.