TM-9-2320-272-23-1
TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)
TECHNICAL MANUAL; FIELD MAINTENANCE MANUAL; VOLUME 1 OF 5
SEPTEMBER 2012
TM-9-2320-272-23-1 - Page 959 of 1313
HEATER WILL NOT OPERATE WITH SWITCH IN LOW POSITION (HIGH POSITION OPERATION NORMAL) -
Continued
STEP
3.
IS CIRCUIT BREAKER IN GOOD CONDITION?
a.
Place battery switch to OFF position.
T0127DAA
To Battery
Switch
To Heater
Switch
569A
569A
Figure 3.
Circuit Breaker Wire 569A.
b.
Disconnect circuit 569A wire to battery switch from circuit breaker.
c.
Place battery switch to ON position.
d.
Connect multimeter red lead to the disconnected end of circuit 569A wire. Refer to point to point
schematics.
e.
Connect multimeter black lead to vehicle chassis ground.
NOTE
If voltage is present, circuit breaker is faulty.
f.
Meter reading should be 12 VDC or greater.
CONDITION/INDICATION
IS CIRCUIT BREAKER IN GOOD CONDITION?
DECISION
NO - Replace circuit breaker (Volume 2, WP
0307). Go to Step (5) to verify problem is solved.
YES - Go to Step (4).
TM 9-2320-272-23-1
0114
0114-4
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