TM 5-3805-262-20
3-24. ACCESSORIES TROUBLESHOOTING (CONT)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
1. AIR HORN DOES NOT SOUND WHEN HORN VALVE DEPRESSED (Cont).
S t e p 2 . ( C o n t ).
Tell assistant to start engine and allow air pressure to build up as
indicated by AIR PRESS gage indication.
Pressure gage installed in tee fitting shall indicate a minimum of
85 psi.
a. If pressure gage indicates a minimum of 85 psi, shut off engine
and replace and repair horn valve (page 10-2).
b. If pressure gage does not indicate a minimum of 85 psi, replace
pressure protection valve (page 7-64).
2. WINDSHIELD WIPER MOTOR DOES NOT OPERATE.
Step 1. Turn ignition key switch to on position.
Pull HEATER FAN switch on cab switch panel out.
Check if heater fan is on.
a. If heater fan is not on, go to step 2 below.
b. If heater fan is on, go to step 5 below.
Step 2.
Press 5 ampere circuit breaker located on right instrument panel.
Check if windshield wiper and heater fan operate.
a .
If both windshield wiper and heater fan operate, problem was
momentary short in circuit. If circuit breaker blows again,
problem is in circuit associated with circuit breaker.
Disconnect wires from circuit breaker, one at a time to isolate
p r o b l e m t o a s s o c i a t e d c i r c u i t : a u x i l i a r y s t e e r i n g , i n s t r u m e nt
panel cluster (located on left instrument panel), voltmeter, cab
relay solenoid, or electric fuel pump.
3-159
