As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER PUSHBACK RT PACK LIGHT ILLUMINATED. IT EXTINGUISHED AFTER A TRIP RESET AND THEN RETURNED. GROUNDED - YES. REMOVED AIR CYCLE MACHINE (RH) PER B737-9 AMM 21-51-04-000-801. FOUND RH ACM CEASED. INSTALLED AIR CYCLE MACHINE REF AMM 21-51-04-400-801 STEP H TO END. OPS CHECK GOOD. AND NO LEAKS NOTED.