What was found
PACK LT OBSERVED ON DURING CLIMBOUT, =18,000, RAN QRH. WARMED TEMP, TRIP RESET, PACK LIGHT CLEARED ON MASTER CAUTION RESET. ACFT GROUNDED. WHILE ON DEFERRAL, AT CRUISE, RT PACK LIGHT ILLUMINATED. FOLLOWED CHECKLIST. LIGHT EXTINGUISHED WHEN MASTER CAUTION SYSTEM WAS RESET. PERFORMED BITE TEST ON NR 2 ZONE TEMP CONTROLLER. FOUND FAULT WAS RAM AIR ACTUATOR. REPLACED RT RAM AIR INLET ACTUATOR IAW AMM 21-51-21-000-801 AND 21-51-21-400-801, OPS CHECK GOOD.