As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON GROUND BOTH MASTER CAUTION AND AIR CONDITION ANNUNCIATOR BLINK ON AND OFF CONTINUOUSLY. ACFT GROUNDED. PERFORMED PACK TEMP CONTROLLER BITE TEST, BOTH NR 1 AND NR 2 TEMP CONTROLLER, NO DEFECTS NOTED. MASTER CAUTION AND A/C LIGHTS EXTINGUISHED. SYS OPS CHECKED OK.