As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB OUT PASSING 15000 FT, CABIN ALTITUDE LIGHT ILLUMINATED. PERFORMED QRH PROCEDURE, VERIFIED ALL SWITCHES WERE CORRECT. MX TROUBLESHOT AIRCRAFT BLEED AND PRESSURIZATION ISSUES IAW AMM 36-11-05, AND 21-00-05. BLEED SYSTEM ON LT & RT ENGINE OPERATES NORMAL. DISCOVERED EQUIPMENT COOLING AUTO FLOW CONTROL VALVE STUCK IN OPEN POSITION. R & R THE AUTO FLOW CONTROL VALVE IAW AMM 21-58-21. OPS CHECKED GOOD. AIRCRAFT GROUNDED.