As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CONTROL CABIN TEMP CONTROLLER HAS NO EFFECT ON DUCT TEMP. MAKING FLIGHT DECK COLD AT ALTITUDE. STUCK AT DUCT TEMP 28 DEGREES CELSIUS. ACFT GROUNDED. ACCOMPLISHED CABIN TEMP CONTROL + INDICATION OPS TEST IAW AMM 21-61-00-700-807-002. COULD NOT DUPLICATE ISSUE, OPS NORMAL.