As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DFW - CREW REPORTED BOTH FUEL HEAT LIGHTS FLICKERED MULTIPLE TIMES AND FUEL TEMPERATURE KEPT RISING TO 55C. EMERGENCY DECLARED FLIGHT RETURNED DFW LANDED WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. REPLACED RIGHT AND LEFT ENGINE FUEL HEAT VALVES. SYSTEM GROUND CHECK NORMAL OPERATION.