TM 5-3805-262-20
3-24. ACCESSORIES TROUBLESHOOTING (CONT)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
9. BOTH REAR DEFOGGER FANS DO NOT OPERATE (Cont).
S t e p 4 . ( C o n t ) .
b . ( C o n t ).
I f c i r c u i t i s o k a y , p r o b l e m i s i n c i r c u i t a s s o c i a t e d w i th
breaker from which wire was disconnected.
Step 5.
Turn DEFROSTER switch on cab switch panel to ON position.
Check if defroster motor operates.
a. If defroster motor operates, check light green wire between 6
ampere circuit breaker and rear defogger fans for open circuit.
Repair or replace wiring (page 5-184).
b. If defroster motor operates, go to step 6 below.
Step 6. Press 6 ampere circuit breaker just below DEFROSTER switch on cab
switch panel.
Check if defroster motor and defogger fans operate.
a. If defroster motor and defogger fans operate, problem was
momentary short in circuit.
b . 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 i n c i r c u i t.
Go to step 7 below.
c. If defroster motor and defogger fans both do not operate,
problem is in 6 ampere circuit breaker. Replace it (page 10-58).
d. If defroster motor operates, but defogger fans do not, check
light green wire between 6 ampere circuit breaker and defogger
fans for open circuit. Replace as necessary.
Step 7.
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 6 am-
p e r e c i r c u i t b r e a k e r t e r m i n a l s.
Disconnect light green wire
spade terminal from 6 ampere
circuit breaker terminal by grasping with your fingers and firmly
pulling from circuit breaker terminal.
3-175
