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CM2150 Electronic Control System – 019-045   Fan Control Circuit

General Information

 TOC

The CM2150 control system can control the fan clutch activation. The ECM energizes the air valve solenoid or an electric fan clutch.

Refer to the OEM troubleshooting and repair manual for more information on the fan clutch wiring.

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The fan control circuit resides in the OEM harness. The fan control signal wire is in the OEM connector on the ECM. The fan control signal wire leads to the fan clutch air solenoid through the OEM wiring harness. The fan control signal is grounded through the clutch body/engine block ground.

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Resistance Check

 TOC

 CAUTION 

Do not use probes or leads other than Part Number 3822758. The connector will be damaged. The leads must fit tightly in the connector without expanding the pins of the connector.

Disconnect the OEM harness connector from the ECM connector. Disconnect the OEM wiring at the fan control solenoid.

Insert a test lead into the fan control signal pin of the OEM harness connector and connect it to the multimeter probe.

Touch the other multimeter probe to the connector terminal of the fan clutch solenoid. Make sure the fan clutch solenoid is disconnected.

Measure the resistance.

The multimeter must show a closed circuit (10 ohms or less). If the circuit is closed, it must still be checked for a short circuit to ground and a short circuit from pin to pin. If the circuit is not closed, there is a connection problem or an open circuit in the wiring harness.

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Check for Short Circuit from Pin to Pin

 TOC

Check for a short circuit between the fan control signal pin and all of the other pins in the OEM harness. Make sure the fan control solenoid is disconnected. Make sure the battery voltage supply is disconnected.

Insert a test lead into the fan control signal pin of the OEM harness connector. Insert the other test lead into all of the other pins of the OEM harness connector, one at a time.

Measure the resistance.

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

If the circuit is not open, there is a short circuit between the fan control signal pin and any pins that measured a closed circuit.

Repair or replace the OEM wiring harness.

Refer to Procedure 019-043 or 019-071.

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Last Modified:  18-Aug-2006
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