If incorrect resistance is indicated when measuring resistance
from pin F of the generator plug to ground, then a resistance
measurement of the APU generator field terminal A to ground must
be made (Figure 32).
APU Generator Field Terminal A.
If resistance of APU generator field terminal A to ground is not
approximately 2 ohms, then the APU generator must be replaced IAW
If APU generator field terminal A resistance
is correct, then a continuity check must be made at terminal H
and L of the APU control box plug. You do this by removing the
APU control box and disconnecting the APU control box plug.
Check continuity by placing multimeter red probe on receptacle
terminal H, and black probe on terminal L.
Now set the APU
GENerator switch to the ON position. Meter should read 0 ohms.
If not, troubleshoot the generator switch and associated wiring
APU Control Box Plug - Terminal H and L.