What was found
COCKPIT PAC IS STUCK ON AND WILL NOT DECREASE IN TEMP. TEMP IS 134 DEGREES INDICATED WITH PAC'S AND BLEED VALVES OFF, ONLY APU RUNNING. CREW COULD DETECT A BURNING ODOR DURING FLT. RAN ACFT AND VERIFIED PROBLEM. INSPECTED COCKPIT PAC FOR SEIZE, FOUND OK. CHECK MIX LUG VALVE AND FOUND OPS CHECK GOOD. SWAPPED THE ECU CONTROLLERS. FOUND DEICE FLUID IN THE ECU CONTROLLER CONNECTOR PLUGS. OBTAINED CONTACT CLEANER AND CLEANED PLUGS. OPS CHECK STILL FAILED. INSPECTED COCKPIT ECU RTD AND EVER HEAT SWITCHES AND FOUND THE SOFT SPLICE BROKEN AT THE TT001 CONNECTOR. REPAIRED SOFT SPLICE AND RESTORED THE ECU CONTROLLERS TO ORIGINALS. ALL OPS CHECKS GOOD ON COCKPIT AND CABIN ENVIRONMENTAL SYSTEMS. ALL CHECKS DONE IAW CHAPTER 21-51-00 OF MM.