As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT DECK VERY COLD EVEN WITH CONT CAB TEMP CONTROL AT FULL HOT. ONLY WAY TO GET HEAT IS ALL CONTROLLERS TO OFF. GROUNDED - YES. VERIFIED FAULT WITH CONT CAB IN FULL WARM, DUCT TEMP FOR CONT CAB GOES TO ALMOST 0 DEGREE FULL COLD AIR BLOWING FROM OUTLETS. INSPECTED AND FOUND CABIN SELECTOR RHEOSTAT FAULTY. RMVD AND INSTALLED NEW P5-17 PNL. REF B737-900 AMM 21-61-07. ACCOMPLISHED SYS OPS TEST REF AMM 21-61-07. NO FAULTS FOUND SYS CKS NORMAL.