As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING OPS CHECKED NOTED THE COCKPIT TEMP CONTROL WOULD NOT OPERATE IN MANUAL OTC AUTO MODE. TURNED ON BLEED AIR, OPENED THE ISOLATION VALVE (UT007), NOTED THE COCKPIT OAC WOULD OPERATE WITH THE ISOLATION VALVE OPEN. R & R ISOLATION VALVE. OPS/LEAK CHECK GOOD. WORK DONE IAW CH 36-10-00 OF THE MM.