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 1169 of 1313
HORN DOES NOT WORK (GAUGES AT NORMAL OPERATING PRESSURE, WARNING BUZZER NOT
SOUNDING) - Continued
STEP
1.
IS THERE AIR AT THE AIR ELECTRIC VALVE?
a.
Start engine and allow air pressure to build to normal operating pressure.
b.
Stop engine.
T0357DAA
AIR ELECTRIC
VALVE
SUPPLY
LINE
Figure 1.
Air Horn.
WARNING
Loosen supply line at valve very slowly. Stop procedure and tighten fitting of supply line
the moment air begins to escape. Failure to comply may result in injury or death to
personnel.
c.
Loosen air supply line very slowly. Refer to point to point schematics.
CONDITION/INDICATION
IS THERE AIR AT THE AIR ELECTRIC VALVE?
DECISION
NO - Replace damaged supply air line (Volume 5, WP
0805). Go to Step (2) to verify problem is solved.
YES - Perform Horn Inoperative electrical circuit troubleshooting (WP
0109).
TM 9-2320-272-23-1
0141
0141-2
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