As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: LH PACK LIGHT ILLUMINATED CLIMBING THROUGH 18,000 FT, TRIP RESET EXTINGUISHED LIGHT BUT RE-ILLUMINATED AFTER 30 SECONDS -- REPEAT ITEM; FLIGHT RETURNED TO FIELD. REPLACED LH PACK TEMPERATURE CONTROL VALVE IAW AMM 21-51-10, OPS CHECK GOOD.