As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB-OUT FROM DTW, CABIN AND FLIGHT DECK BECAME VERY HOT. COM PROCEDURE TO ALLEVIATE HEAT COMING FROM PACK WAS INEFFECTIVE. EMERGENCY WAS DECLARED AND AIRCRAFT RETURNED TO DTW FOR A UNEVENTFUL LANDING. MAINTENANCE REMOVED AND REPLACED 2 TEMP SENSORS, STANDBY PACK TEMP CONTROLLER AND ZONE TEMP CONTROLLER.