Table 1. Engine Fan Circuit Troubleshooting Procedures.

TM 9-2320-303-24-1

Table 1. Engine Fan Circuit Troubleshooting Procedures.

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

Engine Fan Fails to Operate When Coolant Check that engine fan operates

Temperature is 190F to 210F (87C To within 190F to 210F (87C to

98C).

98C) temperature range.

Lack of Fan Clutch Disengagement.

1. Check for air leaks.

Replace failed air tube from air

supply reservoir to fan clutch (WP

2. Check engine fan/modulator If burned out, replace engine fan/

15A fuse.

modulator 15A fuse (WP 0072

3. Check for +12 VDC at engine

fan temperature switch and

engine fan solenoid valve.

4. Check for +12 VDC at circuit If +12 VDC is present, go to step

18 from ignition run power bus. 5. If no voltage is present, repair

circuit 18 from ignition run power

bus.

5. Disconnect lead 234 at line If +12 VDC is present, go to step

disconnect. Check for +12 6. If no voltage is present, repair

VDC at lead 234.

lead 234.

6. Check for continuity between If continuity is indicated, go to

contacts of engine fan step 7. If no continuity is

temperature switch.

indicated, replace engine fan

temperature switch.

7. Check for continuity between If continuity is indicated, repair

contacts of engine fan solenoid ground lead. If no continuity is

valve and ground.

indicated, replace engine fan

solenoid valve (WP 0048 00).