As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE TAXIING OPERATION, AURAL WARNING FROM EQUIPMENT COOLING START HORNING AND DIDNT STOP UNTIL WE RETURNED TO GATE. OVERHEAD OVERHEAT LIGHTING ILLUMINATED. CLEARED AIR INLET FRILL AND AIR CLEANER. REMOVED AND REPLACED FWD RACK SUPPLY AND EXHAUST FANS. ACCOMPLISHED EQUIP EVAL SYS TEST IAW AMM 21-58-00 OPS CHECK GOOD.