As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ORD CREW REPORTED TAIL COMPARTMENT TEMPERATURE HIGH LIGHT ILLUMINATED. EMERGENCY DECLARED FLIGHT RETURNED ORD LANDED WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. FOUND LT HAND PACK HEAT EXCHANGER OUTLET DUCT CLAMP LOOSE. ADJUSTED BOOT & TIGHTENED CLAMP. SYSTEM GROUND CHECKED NORMAL OPERATION CLOSED.