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 917 of 1313
HORN INOPERATIVE - Continued
STEP
1.
DOES HORN ELECTRIC VALVE HAVE AIR SUPPLY?
a.
Check air supply at air electric valve.
T0098DAA
Figure 1.
Horn Air Supply.
b.
Make sure air gauges read normal operating pressure and warning buzzer is not sounding.
c.
Loosen air supply line from horn air electric valve very slowly and listen for air escaping.
CONDITION/INDICATION
DOES HORN ELECTRIC VALVE HAVE AIR SUPPLY?
DECISION
YES - Go to Step (2).
NO - Replace damaged air supply line (Volume 5, WP
0805). Go to Step (7) to verify problem is solved.
STEP
2.
DOES HORN CIRCUIT BREAKER HAVE PROPER INPUT VOLTAGE?
a.
Measure voltage at horn circuit breaker wire 10.
b.
Refer to point to point schematics.
TM 9-2320-272-23-1
0109
0109-2
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