What was found
AT 33,000 FEET, THE RIGHT AIR CONDITIONING PACK FAILED AND CREW WAS UNABLE TO CONTROL CABIN PRESSURIZATION. COMPLIED WITH COM PROCEDURES AND DEPLOYED MASK. INITIATED AN EMERGENCY DESCENT, DIVERTED TO ORD, AND MADE AN UNEVENTFUL LANDING. ON FINAL APPROACH, THE FORWARD ACCESSORY COMPARTMENT "DOOR OPEN" LIGHT ILLUMINATED. MAINTENANCE REPLACED NUMEROUS FLOW CONTROL VALVES AND TEMPERATURE CONTROLLER. FORWARD ACCESSORY DOOR WAS FOUND SECURED AND DOOR LIGHT CHECKED NORMAL. REPACKED OXYGEN MASKS AND REPLACED OXYGEN GENERATORS. AIRCRAFT RETURNED TO SERVICE.