What was found
ETOPS - FOR 3RD CONSECUTIVE FLIGHT ENG 1 WOULD NOT SHUTDOWN ECAM:ENG 1 HP FUEL VALVE NOT CLOSED. PERFORMED TSM 71-00-00-810-925-A FOUND 28VDCAT 3G ON ENG 1 MASTER SWITCH . REMOVED AND REPLACED MASTER SWITCH PER ESPM 20-45-21-0. OPS CHECK FAILED ATTEMPTED (3) STARTS ON 3RD START ENG 1 WOULD NOT SHUTDOWN ECAM: ENG 1 HP VALVE NOT CLOSED. PERFORMED WIRING CHECKS PER TSM 71-00-00-810-925-A. PINS 2+3 AT FMU READ 45.8 OHMS, SOLENOID GOOD. INSPECTED WIRING FROM 3805VC TO 4071KS-C. WIRING LOOKS GOOD. CONTINUITY CHECK FROM PINS 2+3 OF 4071KS-C AND 2 AND 3 OF 3805VCA IS 8.5 OHMS CHECK GOOD. INSULATION RESISTANCE CHECKS FROM 3805VCA PINS 2+3 IS 100GOHMS, GOOD. PIN 2 TO BACKSHELL. READS 25GOHMS, GOOD PIN 3 TO BACKSHELL IS 50GOHMS, GOOD. 28VDC PRESENT AT A3 OF RELAY 3KC1. CHANGED RELAY. 28VDC PRESENT AT PIN 2 OF 4071KS-C. RAN ENG 3 TIMES OPS CHECK GOOD NO DEFECTS NOTED OK FOR SVC.