C Remove APU access panel from APU. Set MASTER switch OFF. Check
voltage at fuel solenoid 421 lead terminal. Place red multimeter probe on 421
terminal and ground black probe. Set MASTER switch ON. Set APU FUEL
SHUT OFF switch ON. If voltage is indicated fuel solenoid is defective.
Notify Support maintenance. If no voltage is indicated, go to step D.
D Set MASTER switch OFF. Disconnect main harness connector (large
connector) at APU wall mount. Place red probe of multiimeter on wall-
mounted connector terminal B, and ground black probe. Set MASTER switch
ON. Set FUEL SHUT OFF switch ON. If voltage is indicated repair or
replace harness 421 from wall-mounted connector to solenoid (p 6- 132). If no
voltage is indicated, go to step E. Reconnect main harness connector.
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TM 9-2350-267-20