APU Harness Wall Connector - Terminal B.
The final test to be made in troubleshooting the APU fuel system is to test
the APU fuel pumps. Ensure the MASTER switch is set to the OFF position.
Disconnect the power leads from the APU fuel pumps and set the MASTER switch
to the ON position. Check the voltage of each fuel pump lead by placing the
multimeter red probe in the lead connector and putting the black probe on a
Now set the FUEL SHUT OFF switch to the ON position.
voltage is indicated and fuel pumps do not operate, replace the fuel pumps.
If no voltage is indicated, repair or replace lead 76 from the fuel pumps to
harness lead 421.
You may now connect the power leads to the APU fuel
pumps. Refer to Figure 18 for this test.
APU Fuel Pump Power Leads.