CHAPTER 2: VEHICLE MAINTENANCE INSTRUCTIONS
TM 9-2350-256-20
2-19 ELECTRICAL TROUBLESHOOTING-Continued
APU HIGH AIR TEMPERATURE SYSTEM-Continued
WARNING
Remove all jewelry such as rings, dog
tags, bracelets, etc. If jewelry contacts a
metal surface a direct short may result in
instant
heating
of
tools,
damage
to
equipment,
and
injury
or
death
to
personnel.
K
Place a jumper wire from wire 27 to terminal of HIGH
AIR TEMP lamp. Place red lead of multimeter on
terminal of lamp and black lead to ground. Turn
MASTER and APU FUEL SHUTOFF switches ON and
check for voltage. Turn MASTER and APU FUEL
SHUTOFF switches OFF. If voltage is present,
repair/replace wire 493 of APU control box wiring
harness (see paragraph 13-7). If voltage is not
present, replace HIGH AIR TEMP lamp (see paragraph
13-7).
L
Reconnect APU control box to foot dimmer switch and
bulkhead wiring harness APU control box. Install APU
control box (9), four screws (8), four lockwashers (7),
and four nuts (6) to mounting bracket. Open air inlet
doors. Disconnect bulkhead to APU, master relay, and
rigger's lights wiring harness from bulkhead disconnect.
Place red lead of multimeter on pin D of wire 493 and
black lead to ground. Turn MASTER and APU FUEL
SHUTOFF switches ON and check for voltage. Turn
MASTER and APU FUEL SHUTOFF switches OFF. If
voltage is present, go to step M. If voltage is not
present, repair/replace wire 493 of APU control box to
foot dimmer switch and bulkhead wiring harness (see
paragraph 6-79 for dual voltage; 6-80 for single
voltage).
2-188
