As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ALL THE VENTS ON THE LT SIDE OF THE ACFT ARE BLOWING FULL HOT. RT SIDE VENTS ARE BLOWING COLD. APU RUNNING WITH ISOLATION VALVE OPEN. AT ONE POINT THERE WAS A STRONG ODOR LIKE BURNING SULFUR COMING FROM THE VENTS. REMOVED ACM IAW MM 21-51-13. OPS CHECKED GOOD. PERFORMED ECS DUCT BURN OUT. ACM LEAK CHECKED GOOD.