As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
COCKPIT TEMP VALVE IN AUTO WENT TO 80 PERCENT FULL HOT. LT DUCT TEMP PEGGED OUT HOT. SLIGHT SMOKE IN COCKPIT. MANUALLY DROVE VALVE FULL COLD. AC SMOKE CHECKLIST RUN. LT BLEED VALVE OFF FOR REST OF FLT. FOUND AUTO TEMP CONTROL TO COCKPIT TEMP SENSOR OUT OF TOLERENCE. ADJUSTED. MANUAL TEMP OPS CHECKED GOOD IAW DC-9 MM 21-60-0. LINES RECONNECTED AND PLACARDS REMOVED.