ALTERNATOR GP-CHARGING 1270300 - Caterpillar

Step 1. CHECK FOR PROPER OPERATION
Occupy the seat.
Place the armrest in the DOWN position.
Turn the key start switch to the ON position.
Press and release the parking brake switch.Expected Result:The parking brake indicator should be off.Results:
OK - The parking brake indicator is off.Repair: There is no problem at this time. Stop.
NOT OK - The parking brake indicator is on and the armrest indicator is off. Proceed to Test Step 2.
NOT OK - The parking brake indicator is on and the armrest indicator is flashing.Repair: See Troubleshooting, "Armrest Indicator Is Flashing". Stop.
NOT OK - The parking brake indicator is flashing.Repair: The parking brake indicator is not working properly. See Troubleshooting, "Parking Brake Indicator Is Flashing". Stop.Test Step 2. CHECK THE PARKING BRAKE SWITCH
Turn the key start switch to the OFF position.
Remove the parking brake switch.
Disconnect the wire harness from the switch.
Press the switch.
Measure the resistance from terminal 2 to terminal 3 of the parking brake switch.Expected Result:The resistance should be less than 5 Ohms.Results:
OK - The resistance is less than 5 Ohms. Proceed to Test Step 3.
NOT OK - The resistance is not less than 5 Ohms.Repair: The parking brake switch has failed. Replace the parking brake switch. Stop.Test Step 3. CHECK THE CIRCUIT FOR THE PARKING BRAKE SWITCH
Jumper wire F780-PK to wire 201-BK in the wire harness for the parking brake switch.
Raise the cab. See Operation and Maintenance Manual, "Cab Tilting".
Locate the interlock ECM. The interlock ECM is located on the left side of the machine beneath the access cover on the floor of the machine.
Disconnect the wire harness from the ECM.
Measure the resistance from contact 42 to contact 3 (wire F780-PK to wire 201-BK) on the wire harness connector.Expected Result:The resistance should be less than 5 Ohms.Results:
OK - The resistance is less than 5 Ohms.Repair: The ECM is very unlikely to have failed. Reconnect all connections and visually inspect the wire harness. Verify that the diagnostic code still exists. If the diagnostic code still exists perform the Test Steps again.Replace the ECM, if the cause of the diagnostic code was not found after the second attempt. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace". Stop.
NOT OK - The resistance is greater than 5 Ohms.Repair: The wire harness has an open. Repair the wire harness and/or the connector or replace the wire harness and/or the connector. Stop.