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 919 of 1313
HORN INOPERATIVE - Continued
STEP
3.
DOES HORN CIRCUIT BREAKER HAVE PROPER OUTPUT VOLTAGE?
a.
Check for battery voltage at horn circuit breaker terminal.
b.
Place battery switch to the OFF position.
T0100DAA
10
26
Figure 3.
Horn Circuit Breaker Test.
c.
Refer to point to point schematics.
d.
Reconnect circuit 10 wire and disconnect circuit 26 wire from circuit breaker.
e.
Place battery switch to ON position.
f.
Connect multimeter red lead to open circuit 26 terminal on circuit breaker.
g.
Connect multimeter black lead to vehicle chassis ground.
h.
Metter reading should be greater than or equal to 18 VDC.
CONDITION/INDICATION
DOES HORN CIRCUIT BREAKER HAVE PROPER OUTPUT VOLTAGE?
DECISION
YES - Go to Step (4).
NO - Replace circuit breaker (Volume 2, WP
0307). Go to Step (7) to verify problem is solved.
TM 9-2320-272-23-1
0109
0109-4
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