As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
A STRONG "SULPHUR" BURN SMELL WAS NOTED AT ALTITUDE 410 FL.. NO SMOKE NOTED BUT SMELL WAS PRESENT UNTIL AFTER LANDING. DURING THIS TIME, NOTICED THAT CABIN PACK TEMPERATURE COULD NOT BE CONTROLLED IN AUTO OR MANUAL. TEMPERATURE STAYED AT MAX HEAT. CABIN PACK WAS SHUT OFF TO CONTROL TEMPERATURE. ITEM IS UNDER INVESTIGATION.