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TM 5-3805-262-20
3-24. ACCESSORIES TROUBLESHOOTING (CONT)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
2. WINDSHIELD WIPER MOTOR DOES NOT OPERATE (Cont).
S t e p 4 . ( C o n t ).
b. If multimeter indicates 24 volts, a short circuit to ground
e x i s t s i n c a b e l e c t r i c a l c i r c u i t . I s o l a t e d e f e c t i v e c i r c u i t b y
reconnecting wire from cab relay BAT. terminal to long, silver
terminal of cab circuit breaker. Then, at cab switch panel, dis-
connect and tape wires connected to each of the three circuit
breakers one at a time and check if remaining circuit(s) operate
when associated switch is operated. If circuit is okay, problem
is in circuit associated with breaker from which wire was dis-
connected.
Step 5.
Press 3 ampere circuit breaker on cab switch panel.
Check if windshield wiper operates.
a. If windshield wiper operates, problem was momentary short in
c i r c u i t . I f c i r c u i t b r e a k e r b l o w s , a s h o r t t o g r o u n d e x i s t s in
circuit. Isolate by checking wiring for worn insulation. If
wiring okay, perform resistance check of wiper motor. Replace
parts as necessary (page 10-13).
b. If windshield wiper does not operate, go to step 6 below.
Step 6. Turn ignition key switch to off
p o s i t i o n.
Remove HEAT CONTROL knob from
cab switch panel by pulling
s t r a i g h t u p o f f c o n t r o l s h a f t .
Remove four screws securing cab
switch panel.
Carefully pull cab switch panel
upwards from heater console just
enough to gain access to FRONT
WIPER switch terminals.
Connect multimeter between FRONT
WIPER switch B terminal and
c h a s s i s .
Turn ignition key switch to on
p o s i t i o n.
Multimeter shall indicate 24 volts.
a. If 24 volts not obtained, replace 3 ampere circuit breaker (page
10-18).
3-161
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