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 965 of 1313
HEATER WILL NOT OPERATE WITH SWITCH IN HIGH POSITION (LOW POSITION OPERATION NORMAL) -
Continued
STEP
3.
IS CIRCUIT BREAKER IN GOOD CONDITION?
a.
Check for battery voltage at circuit 5A wire.
b.
Place battery switch to OFF position.
T0132DAA
27
5A
Figure 3.
Circuit Breaker Wire 5A.
c.
Disconnect circuit 5A wire to battery switch from circuit breaker.
d.
Place battery switch to ON position.
e.
Connect multimeter red lead to the disconnected end of circuit 5A wire. Refer to point to point schematics.
f.
Connect multimeter black lead to vehicle chassis ground.
NOTE
If voltage is present, circuit breaker is faulty.
g.
Meter reading should be greater than 18 VDC.
CONDITION/INDICATION
IS CIRCUIT BREAKER IN GOOD CONDITION?
DECISION
NO - Replace circuit breaker (Volume 2, WP
0307). Go to Step (4) to verify problem is solved.
YES - Repair or replace circuit 5A wire (Volume 3, WP
0352). Go to Step (4) to verify problem is solved.
TM 9-2320-272-23-1
0115
0115-4
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