TM 9--2350--292--20--1
0018 00--4
AUXILIARY POWER UNIT FAILS TO CRANK -- CONTINUED
0018 00
no
yes
CONTINUED FROM STEP F
G
Is continuity present?
H
no
yes
CONTINUED ON
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Replace preheat relay (WP 0664 00).
Verify fault is corrected.
Repair (WP 0290 00) or replace
(WP 0649 00) harness 3W711.
Verify fault is corrected.
1. Reconnect lead P to preheater relay.
2. Disconnect lead 487 at preheater relay.
3. Place multimeter red lead to preheater relay
terminal and black lead to ground.
4. Turn MASTER switch ON
(TM 9--2350--292--10).
5. Turn PREHEAT switch to MOM ON
(TM 9--2350--292--10). Check for voltage.
6. Turn MASTER switch OFF.
Is 24 V dc present?
1. Disconnect harness 3W702 J1 from harness
3W711 P1.
2. Place multimeter red lead to lead 487 and
black lead to pin D of harness 3W711 P1.
3. Check for continuity.
no
yes
I
Replace diode (WP 0639 00).
Verify fault is corrected.
Is 24 V dc present?
1. Reconnect harness 3W711 P1 to harness
3W702 J1.
2. Reconnect lead 487 to preheater relay.
3. Disconnect harness 3W711 lead S from
diode terminal.
4. Place multimeter red lead to diode terminal
and black lead to ground.
5. Turn MASTER switch ON
(TM 9--2350--292--10).
6. Turn PREHEAT switch to MOM ON
(TM 9--2350--292--10). Check for voltage.
7. Turn MASTER switch OFF.
