TM9-2320-363-20-1
Table 3-1.
Troubleshooting
(Cont)
Malfunction
Test or Inspection
Corrective Action
ELECTRICAL SYSTEM (CONT)
Engine Brake Retard Circuits (Cont)
Step 4.
Disconnect lead 121D from line disconnect to rear
solenoid valve. Check for +12 VDC at lead 121D.
.
If +12 VDC
is present,
go to step 5.
repair lead 121D
(page 3-2).
cylinders engine
If no voltage is
Step 5.
Check for continuity between
contact of rear cylinders
engine brake
brake
present,
solenoid
valve to ground, and contact of front cylinders engine
brake solenoid valve
to ground.
l
If continuity is indicated,
notify direct support maintenance.
If
no continuity is indicated,
repair faulty ground (page 3-2).
Engine Fan Circuit
1.
ENGINE
FAN
FAILS TO OPERATE
WHEN
COOLANT
TEMPERATURE
IS 190°F
TO 210°F
(87°C
TO 98°C).
Check that engine fan operates within 190 ‘F
to 210°F
(87°C
to 98°C)
temperature
range.
.
Replace fan clutch temperature
switch (page 4-236).
2.
LACK OF FAN CLUTCH
DISENGAGEMENT.
Step 1.
Check
for air leaks.
.
Replace failed air tube from air supply reservoir to fan clutch
(pages 4-487,
4-503).
Step 2.
Check
engine fan/modulator
15A fuse.
.
If burned out, replace
engine fan/modulator
15A fuse
(page 4-204).
3-27
