What was found
EN ROUTE LGW-CLT, CREW COULD NOT CONTROL TEMPERATURE IN THE CABIN. THE FLIGHT TURNED BACK TO LGW, HOWEVER, THE CREW WAS ADVISED TO TURN BOTH HEAT SOURCES OFF. THIS ACTION EVENED OUT THE TEMPERATURE THROUGHOUT THE CABIN. FLIGHT THEN RESUMED ITS ROUTE TO CLT. FLIGHT DIVERTED TO PHL FOR FUEL. MAINTENANCE REPLACED THE AFT ZONE TEMPERATURE CONTROLLER. (M)