TM-9-2350-311-20-2
HOWITZER, MEDIUM, SELF-PROPELLED, 155MM; M109A2, M109A3, M109A4 AND M109A5
TECHNICAL MANUAL; UNIT MAINTENANCE MANUAL FOR CAB, ARMAMENT, SIGHTING AND FIRE CONTROL, ELEVATING AND TRAVERSING SYSTEMS AND ASSOCIATED COMPONENTS
DECEMBER 1993
TM-9-2350-311-20-2 - Page 196 of 828
TM 9–2350–311–20–2
3–84
3–3
TROUBLESHOOTING — CONTINUED
g.
CAB POWER SYSTEM — CONTINUED
(1)
ALL CAB ELECTRICAL COMPONENTS FAIL
TO OPERATE. — CONTINUED
1.
Turn MASTER switch to OFF.
2.
Reconnect J2 harness connector at gunner’s
selector switch box assembly.
3.
Open gunner’s selector switch box assembly.
4.
Turn MASTER switch to ON.
5.
Place red multimeter lead on circuit breaker input
terminal A and black lead to ground.
6.
Check for voltage.
Is battery voltage present?
1.
Place red multimeter lead on circuit breaker
output terminal B and black lead to ground.
2.
Check for voltage.
Is battery voltage present?
Repair wire 100 from har-
ness connector to circuit
breaker (para 8–12).
G
yes
no
CONTINUED ON NEXT PAGE
CONTINUED FROM STEP F
H
yes
no
Replace circuit breaker
(para 8–12).
GUNNER’S SELECTOR
SWITCH BOX ASSEMBLY
INPUT TERMINAL A
–
+
GUNNER’S SELECTOR
SWITCH BOX ASSEMBLY
OUTPUT TERMINAL B
–+
CIRCUIT BREAKER
CIRCUIT BREAKER
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