CM850 Electronic Control System – 019-329   Fan Clutch Switch

General Information

TOC

The fan clutch switch allows the driver to control the operation of the engine’s fan.

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Resistance Check

TOC

If INSITE™ electronic service tool is available, monitor the fan clutch switch for proper operation. If
not, follow the troubleshooting procedures in this section.

Locate the fan clutch switch. Remove and tag the two connectors from the terminals on the switch.

Touch the multimeter probes to the terminals on the switch.

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Move the switch to the OFF position, and measure the resistance.

The multimeter
must show 100k ohms or more (open circuit).

If the circuit is
not open, the switch has failed.

Replace the switch. Refer to the OEM troubleshooting and repair manual for the replacement instructions.

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Move the switch to the ON position, and measure the resistance.

The multimeter
must show 10 ohms or less (closed circuit).

If the circuit is
not closed, the switch is damaged and
must be replaced. Refer to the OEM repair manual for the replacement instructions.

If the resistance value is correct, the switch
must still be checked for a short circuit to ground.

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Check for Short Circuit to Ground

TOC

Touch one of the multimeter probes to one of the switch terminals. Touch the other probe to chassis ground.

Move the switch to the ON position, and measure the resistance.

The multimeter
must show 100k ohms or more (open circuit).

If the circuit is
not open, the switch is damaged and
must be replaced. Refer to the OEM repair manual for replacement procedures.

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Last Modified:  30-May-2008