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 958 of 1313
HEATER WILL NOT OPERATE WITH SWITCH IN LOW POSITION (HIGH POSITION OPERATION NORMAL) -
Continued
STEP
2.
IS THERE PROPER VOLTAGE AT CIRCUIT 569A TERMINAL OF CIRCUIT BREAKER?
a.
Place battery switch to OFF position.
T0126DAA
To Battery
Switch
To Heater
Switch
569A
569A
Figure 2.
Circuit Breaker Wire 569A.
b.
Disconnect circuit 569A wire to heater switch from circuit breaker.
c.
Place battery switch to ON position.
d.
Connect multimeter red lead to the open circuit 568A terminal on circuit breaker. Refer to point to point
schematics.
e.
Connect multimeter black lead to vehicle chassis ground.
f.
Meter reading should be 12 VDC or greater.
CONDITION/INDICATION
IS THERE PROPER VOLTAGE AT CIRCUIT 569A TERMINAL OF CIRCUIT BREAKER?
DECISION
YES - Repair or replace circuit 569A wire between circuit breaker and heater switch (Volume 3, WP
0352). Go
to Step (5) to verify problem is solved.
NO - Go to Step (3).
TM 9-2320-272-23-1
0114
0114-3
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