HARNESS AS-SWITCH 3156417 - Caterpillar

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Schematic
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P1 ECM connectorTest Step 1. Inspect Electrical Connectors and Wiring
Turn the keyswitch to the OFF/RESET position.
Thoroughly inspect the J1/P1 ECM connector and all other connectors in the circuit. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.Expected Result:All connectors, pins, and sockets are completely 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 - Proceed to Test Step 2.
Not OK - Repair: Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 2. Verify Operation of the Engine Fan Reverse Switch
Connect the Caterpillar Electronic Technician (Cat ET) to the service tool connector.
Turn the keyswitch to the ON position.
Check the status of the engine fan reverse switch on Cat ET while you operate the switch.
Turn the keyswitch to the OFF/RESET position.Expected Result:The status of the switch changes accordingly as you operate the switch.Results:
OK - The status changes accordingly with the switch position. Proceed to Test Step 3.
Not OK - The status does not change with the switch position. Proceed to Test Step 8.Test Step 3. Check the resistance through the Fan Reversing Solenoid
Disconnect the fan reversing solenoid.
Measure the resistance of the solenoid at the connector terminals.Expected Result:Resistance is between 25 and 40 Ohms.Results:
OK - The resistance of the solenoid is within the specified range. Proceed to Test Step 5.
Not OK - The resistance of the solenoid is out of the specified range. Proceed to Test Step 4.Test Step 4. Temporarily Install a New Solenoid
Remove the solenoid.
Temporarily install a new solenoid.
Verify that the new solenoid corrects the problem.
Turn the keyswitch to the OFF/RESET position.Expected Result:The new solenoid corrected the problem.Results:
OK - The solenoid was faulty.Repair: Permanently install the new solenoid.Verify that the repair eliminates the problem.STOP
Not OK - There may be a problem with the wiring harness. Proceed to Test Step 5.Test Step 5. Check for a Short in the Harness
Ensure that the keyswitch is in the OFF/RESET position.
Disconnect the J1/P1 ECM connector and disconnect the reversing fan solenoid.
Measure the resistance between P1:10 (Reversing Fan Solenoid) and chassis ground.Expected Result:The resistance is greater than 20,000 Ohms.Results:
OK - The wiring harness is not shorted to ground. Proceed to Test Step 6.
Not OK - There is a short to ground between the ECM and the solenoid.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 6. Check for an Open in the Harness
Ensure that the keyswitch is in the OFF/RESET position.
Use a suitable piece of wire to short terminal 1 of the harness connector for the fan reversing solenoid to chassis ground.
Measure the resistance between P1:10 (Reversing Fan Solenoid) and chassis ground.Expected Result:The resistance is less than 10 Ohms.Results:
OK - There is not an open in the circuit. Proceed to Test Step 7.
Not OK - There is an open circuit between the ECM and the solenoid.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 7. Temporarily Install a New ECM
Temporarily install a new ECM. Refer to Troubleshooting, "Replacing the