TM9-2320-363-20-1
Table 3-1.
Troubleshooting
(Cont)
Malfunction
Test or Inspection
Corrective Action
ELECTRICAL
SYSTEM (CONT)
Engine Fan Circuit (Cont)
Step 3.
Check for +12 VDC
at engine
fan temperature
switch
solenoid valve.
.
If +12
VDC
is present,
go to step 6.
.
If no voltage
is present,
go to step 4.
and engine fan
Step 4.
Check
for +12 VDC
at circuit 18 from ignition run power bus.
.
If +12
VDC
is present,
go to step 5. If no voltage
is present,
repair circuit 18 from ignition run power bus (page 3-2).
Step
5.
Disconnect
lead 234
at line disconnect.
Check for +12
VDC
at lead 234.
.
If +12
VDC
is present,
go to step 6. If no voltage
is present,
repair lead 234
(page
3-2).
Step
6.
Check for continuity
between
contacts
.
If continuity
is indicated,
indicated,
replace
engine
Step
7.
Check
for continuity between
contacts
ground.
.
If continuity
is indicated,
of engine fan temperature
switch.
go to step 7. If no continuity is
fan temperature
switch (page 4-124).
of engine fan solenoid valve and
repair ground lead
(page 3-2).
If no
continuity
is indicated,
replace
engine fan solenoid valve
(page
4-124).
Step
8.
Refer
to DDEC
II troubleshooting
(page 3-101).
Headlight
Circuits
1.
NEITHER
HEADLIGHT
OPERATES
WHEN
SWITCH
IS TURNED
ON.
Step
1.
Check
left and right headlight
15A fuses.
.
If defective,
replace
15A fuses (page 4-204).
Step 2.
Disconnect
lead 420M
from vehicular
light switch. Check for +12 VDC
at
pin M.
.
If +12
VDC
is present
at vehicular
light switch, go to step 3. If
no voltage
is present
at vehicular
light switch,
replace vehicular
light switch (page
4-170).
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