ALTERNATOR GP-CHARGING 4N6559 - Caterpillar

is the same regardless of the position of the Range Switch.Note: If the Range Switch is in the GND position, ET will display "9-16". If the Range Switch is not in the GND position, ET will display "1-8".Results:
YES - The Dial Setting is the same regardless of the position of the Range Switch. Proceed to Test Step 4.
NO - The Dial Setting is not the same regardless of the position of the Range Switch. Proceed to Test Step 5.Test Step 4. VERIFY WIRING IS CORRECT
At the Circuit Board, disconnect Connector A-C3.
Disconnect the harness connector J1 at the ECM.
Place a jumper wire between Pin 7 and Pin 9 on Connector A-C3.
Measure the resistance between J1-32 (Wire F457-BR) and J1-13 (Wire 201-BK).Expected Result:The resistance measurement is less than 2 ohms.Results:
YES - The resistance measurement is less than 2 ohms. The Wiring to the Circuit Board is correct. the Circuit Board is failed.Repair: Replace the Circuit Board.STOP
NO - The resistance measurement is greater than 2 ohms. The wiring to the Circuit Board is failed.Repair: Repair the wiring.STOPTest Step 5. CHECK THE DROP DIAL READING The machine remains connected to Cat ET.Results:
YES - The setting of the Drop Dial matches the reading in Cat ET. Proceed to Test Step 7.
NO - The setting of the Drop Dial does not match the reading in Cat ET. Proceed to Test Step 6.Test Step 6. VERIFY WIRING IS CORRECT
At the Operator Monitor, disconnect Connector X-C1.
At the ECM, disconnect the J1 harness connector.
At Connector X-C1, place a jumper wire between Pin 1 (Wire 123-RD) and Pin 4 (Wire 171-RDBK).
At the J1 connector for the ECM, measure the resistance between J1-33 (Wire F458-GN) and J1-62 (Wire H464-GY).
Remove the previous jumper. At Connector X-C1, place a jumper wire between Pin 2 (Wire 124-BK) and Pin 3 (Wire 125-WH).
At the J1 connector for the ECM, measure the resistance between J1-34 (Wire F459-WH) and J1-35 (Wire F456-PK).Expected Result:All resistance measurements are less than 2 ohms. The wiring to the Drop Dial Switch is correct.Results:
YES - All resistance measurements are less than 2 ohms. The wiring to the Drop Dial Switch is correct. The Monitor is failed.Repair: Replace the Monitor.STOP
NO - There is a resistance measurement greater than 2 ohms. The wiring to the Drop Dial Switch is not correct.Repair: Correct the wiring.STOPTest Step 7. CHECK THE REVERSE CURRENT TRANSDUCER
Access the "Status" screen in Cat ET.
The generator must be running.
Press the "Lift" switch.
Monitor the "Reverse" current in Cat ET.
Press the "Drop" switch.Expected Result:The Reverse current increases to greater than 1 amp during the "Drop" cycle. The Reverse Current Transducer is OK.Note: The "Reverse" current will fluctuate between 0 and the setting of the Drop Dial.Results:
YES - The Reverse Current Transducer is OK. Proceed to Test Step 8.
NO - The Reverse Current Transducer is failed.Repair: Replace the Reverse Current Transducer.STOPTest Step 8. MEASURE THE VOLTAGE
Set the digital multimeter to the scale for VDC.
Connect the positive lead of the multimeter to J2-3 (Wire G889-GY). Connect the negative lead of the multimeter to J1-70