What was found
CARGO HEAT INOP. REPLACED CARGO COMP TEMP SENSOR, NO HELP. TRIED CARGO HEAT CONTROLLER 10HC, NO HELP. REINSTALLED ORIGINAL CONTROLLER. CARGO HOT AIR VALVE WILL NOT OPEN. CANNOT REGULATE TEMP USING CARGO HEAT SELECTOR. REPLACED AFT CARGO PIT TEMP SENSOR, HOT AIR VALVE, PRESS REG VLV, NO HELP. SWAPPED OUT CONTROLLER, NO HELP. AFT CARGO DOOR BEING OPEN INHIBITS AFT CARGO HEAT. POSSIBLE DOOR SW FAULT, 12MJ PCN 565-1759. REPLACED LGCIU NR 1. OPS CHECKS OKAY.