As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PRIOR TO DESCENT, LEFT PACK LIGHT ILLUMINATED DURING MASTER CAUTION RECALL AND EXTINGUISHED WHEN MASTER CAUTION SYSTEM WAS RESET. GROUNDED - YES. C/W LEFT PACK LIGHT ON B737-800 FIM 21-53 TASK 821 & PACK TEMPERATURE CONTROL BITE PROCEDURE PER FIM 21-62 TASK 801, NO FAULTS FOUND. LEFT PACK LIGHT REMAINS EXTINGUISHED.