What was found
RCVD LEVEL 2 AVIONICS AIR FLOW OFF, THEN AVIONICS FAN O'VRD CAME ON. NO -ESC- CURRENT FAULTS NOTED, -ESC- FAULT REVIEW INDICATES NO FAULTS LAST LEG, -EC- SENSOR READOUTS NORMAL. PERFORMED -ESC- RETURN TO SERVICE CK, SYS PASS. REMOVED AND REPLACED ENV SYSTEM CONTROLLER PER MD11 AMM 21-08-01-4, REMOVED AND REPLACED AIRFLOW SWITCH S1-139 PER MD11 AMM 21-26-05-2. ABLE TO DUPLICATE PROBLEM, WITH A/C PRESSURIZED AT 1.4 DELTA PSI. PRESSURIZED A/C AGAIN AFTER PARTS CHANGED, AND OPERATIONAL CHECK OF AVIONICS COOLING NORMAL, AND NO LEAKS NOTED IN A/C STRUCTURE.