FK616917 Force STARTER RELAY

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Location of the manual purge switch for the cooling fan reversing solenoid (1) Manual purge switch
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Location of the cooling fan reversing solenoid (2) Control Manifold Gp (3) Cooling fan reversing solenoidThe purpose of a reversing fan is to clean debris from the radiator. By temporarily reversing the direction of the air flow through the radiator fins, debris is purged from the radiator fins. For some applications, the reversing fan is used to heat the engine compartment during cold-weather operation.In the automatic mode, the fan reversing solenoid is controlled by the Electronic Control Module (ECM). The ECM will automatically reverse the direction of the rotation of the fan. The ECM will use a preset time interval to cycle the fan reversing solenoid. The operator can manually reverse the rotation of the fan by pressing the manual purge switch. While the momentary switch is depressed, the direction of the fan rotation will reverse. Once the switch is released by the operator, the fan returns to normal operation and control of the fan will return to the automatic operation.
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Schematic for the cooling fan reversing solenoid and manual purge switchTest Step 1. Inspect the Electrical Connectors and the Wiring
Turn the keyswitch to the OFF position.
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Location of the ECM connectors (4) J1/P1 ECM connectors
Thoroughly inspect the connectors for purge switch (1) , cooling fan reversing solenoid (3) , and ECM connectors (4) . Also, thoroughly inspect all of the other connectors in the wiring harness. Refer to Troubleshooting, "Electrical Connectors - Inspect" for information related to inspecting connectors.
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Terminal locations at the J1/P1 ECM connectors (P1-5) Return (P1-12) Reversing solenoid (P1-18) Return (P1-46) Manual purge switch
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Terminal locations at the manual purge switch (Terminal 2) Return (Terminal 3) Signal
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Terminal locations at the cooling fan reversing solenoid (Terminal 1) Solenoid signal (Terminal 2) Return
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector and the sensor connectors that are associated with the active diagnostic code.
Check the allen head screw for each ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect".Expected Result:All connectors, pins, and sockets are inserted and coupled. The harness and wiring are free of corrosion, of abrasion, and of pinch points. All connections and grounds are tight and free of corrosion.Results:
OK - The harness and wiring are OK. Proceed to Test Step 2.
Not OK - There is a problem with the harness and/or wiring.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 2. Check the Resistance of the Solenoid Coil
Turn the keyswitch to the OFF position.
Disconnect the reversing solenoid for the variable pitch fan.
Measure the resistance between 1 (solenoid) and 2 (Return).The correct resistance of the solenoid coil at 25° C (77° F) ... 32 1.6 OhmsExpected Result:The resistance of the solenoid coil is within specifications.Results:
OK - The resistance of the coil is within specifications. The coil is OK. Proceed to Test Step 3.
Not OK - The resistance is not within specifications.Repair: There is a problem with the coil. Install a new cooling fan reversing solenoid.Verify that the repair eliminates the problem.STOPTest Step 3. Use Caterpillar Electronic Technician (ET) to Check the Status of the Manual Purge Switch
Connect Cat ET to the service tool connector.
Turn the keyswitch to the ON position.
Observe the status for Engine Fan Reverse Switch Position on Cat ET while you operate the switch.
Turn the keyswitch to the OFF position.Expected Result:The status of the switch is "On" when the switch is depressed. The status reads "Off" when the switch is released.Results:
OK - The status shows the expected result. The manual purge switch is working properly. Proceed to Test Step 5.
Not OK - The status does not show the expected result. The ECM does not recognize the input from the manual purge switch. Proceed to Test Step 4.Test Step 4. Check the Manual Purge Switch
Turn the keyswitch to the OFF position.
Disconnect the connector for the manual purge switch.
Measure the continuity between P1-46 (manual purge switch) and P1-5 (return) with the manual purge switch in the released position.
Measure the continuity between P1-46 (manual purge switch) and P1-5 (return) with the manual purge switch in the depressed position.Expected Result:There is no continuity between P1-46 (manual purge switch) and 5 (return) when the switch is in the released position. There is continuity between 46 (manual purge switch) and P1-5 (return) when the switch is in the depressed position.Results:
OK - There is no continuity when the switch is in the released position. There is continuity when the switch is in the depressed position. Proceed to Test Step 5.
Not OK - The continuity of the circuit is not acceptable. There is a problem with the manual purge switch.Repair: Replace the manual purge switch with a new switch.Verify that the repair eliminates the problem.STOPTest Step 5. Check for a Short in the Harness for the Cooling Fan Reversing Solenoid
Disconnect the J1/P1 ECM connector.
Measure the resistance between P1-46 (manual purge switch) and chassis ground.