As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CONT CAB TEMP CONTROL KNOB WILL MODULATE THE CONT CAB SUPPLY DUCT TEMPERATURE UP + DOWN WITH A MOVEMENT UP + DOWN BY THE KNOB. THE LOWEST TEMPERATURE WE COULD ACHIEVE WAS 50'C HOWEVER- TOO HOT!. GROUNDED - YES. REMOVED AND REPLACED LH PACK TEMP CONTROL VALVE REF B737-900 AMM 21-51-10-400-801.