What was found
ON CLIMB OUT, PASSING FL180, LEFT "PACK" LIGHT ILLUMINATED. FOLLOWED THE QRH AND TURNED ALL TEMP SELECTORS WARMER AND PUSHED THE "TRIP RESET" BUTTONS. THE "PACK" LIGHT WENT OUT MOMENTARILY BUT CAME BACK ON. FOLLOWED QRH PROCEDURES AND CLOSED THE ISOLATION VALVE AND TURNED THE LEFT PACK SWITCH TO OFF. LEFT "PACK" LIGHT REMAINED EXTINGUISHED FOR REST OF THE FLIGHT. GROUNDED - YES. REPLACED LT RAM AIR INLET DEFLECTOR DOOR SHAFT ASSY & UPPER/LWR SUPPORT BEARING ASSY'S REF AMM 21-51-22-000-802 & 21-51-22-400-802. RAM AIR INLET DEFLECTOR DOOR & MODULATION PANELS ADJUSTMENTS CHECK GOOD REF AMM 21-51-22-400-803. LT PACK/ZONE TEMP CONTROLLER BITE TEST GOOD REF AMM 21-61-00-700-806. NO DEFECTS NOTED. INLET DEFLECTOR DOOR OP'S CHECK GOOD.