As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED AND THE AIRCRAFT RETURNED TO DFW DUE TO A CIDS PANEL CAUTION LIGHT FOR THE AFT CARGO DRAIN MAST HEATER FAIL. THE AIRCRAFT LANDED SAFELY AT DFW AND TAXIED TO THE GATE UNDR ITS OWN POWER. **SUPPLEMENTAL REPORT WILL BE SUBMITTED** (OPEN)