As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR TURNBACK - EQUIP COOLING, OFF LIGHT ILLUMINATED. HEAT SMELL DISSIPATED IMMEDIATELY IN COCKPIT BUT LINGERED IN CABIN. FOUND NORMAL EQUIPMENT COOLING BLOWER AND CHECK VALVE BAD. REMOVED AND REPLACED BLOWER, CHECK VALVE AND HEPA FILTER PER MM.