As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR TURNBACK TO DTW. RT ACM TEMP IS UNCONTROLLABLE AND RT BLEED CLOSED AND WOULD NOT REOPEN. MAINTENANCE VERIFIED PIREP, CLEANED AND RESECURED CANNON PLUG TO RT DUAL TEMP CONTROL VALVE. GROUND RAN A/C FOR 30 MINUTES. OPS CHECK OF RT TEMPERATURE SYSTEM GOOD AT THIS TIME.