What was found
LEFT "PACK" LIGHT ILLUMINATED ON PRESURIZATION PANEL PASSING FL180 DURING CLIMB. LIGHT EXTINGUSHED AFTER RUNNING QRH PROCEDURE WITH TRIP RESET APPROX 2 MIN LATER LEFT "PACK" LIGHT CAME ON AGAIN AND PACK WAS SHUT OFF PER QRH PROCEDURE - LIGHT REMAINED ILLUMIUATED. DUCT PRESSURE ON BOTH SIDES LOOKED NORMAL - APPROX 40 PSI - LEFT PACK TEMP SEEMED HIGH, COOLED AT CRUZE. GROUNDED - YES. FOUND LH RAM AIR INLET ACTUATOR OUT OF RIG AND ITS ROD END HAVING A LOT OF SLP BETWEEN IT AND ACTUATOR BODY REPLACED THE LH RAM AIR INLET ACTUATOR REF B737-800 AMM 21-51-21/401.