As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER START HAD "L" PACK LIGHT ON RECALL. RESETS. GROUNDED - YES. LH PACK PRIMARY TEMP CTL INOP. PERFORMED B737-800 FIM 21-62, FOUND PACK RAM ACTUATOR FAULT, VERIFY GO, RESET AND TESTED AGAIN WITH NO FAULT. PERFORMED FURTHER TROUBLESHOOTING WITH OPS TEST OF RADA, TEST PASS REF B737-800 AMM 21-51-00-730-802.