BCU 523692.05 – Upper Worklights on Cab Frame On, No Current Present at Power Module PC0. John Deere System Advisory.

BCU 523692.05 (BCU )

Code: 523692.05



Error code BCU 523692.05 is triggered when the Power Module PC0 in a John Deere vehicle measures a current of less than 500 mA at lead 1029 for the upper worklights on the cab frame (E35) while they are switched on. This diagnostic trouble code suggests an open circuit within the wiring or connections, preventing adequate current from reaching the worklights, thereby impairing their functionality.


The system likely will not illuminate the upper worklights due to the insufficient current, impacting visibility and potentially compromising safety during operations requiring enhanced lighting, particularly in low-light conditions.


  • Inspect Worklight Fixtures and Wiring: Check the upper worklights and their wiring for any signs of disconnection, damage, or wear that could be causing the open circuit.
  • Test Electrical Connections: Use a multimeter to test the continuity and voltage output at lead 1029 to pinpoint the location and nature of the open circuit.
  • Repair or Replace Faulty Wiring or Components: If any breaks or disconnections are found, repair the wiring or replace the faulty components to ensure the correct functioning of the worklights. Make sure all connections are secure and properly insulated.
  • Evaluate Power Module PC0: Verify that Power Module PC0 is functioning correctly and is capable of delivering adequate power to the worklights. Replace the module if it shows signs of malfunction or damage.
  • Reset the Power Module and BCU: After repairs are completed, reset the power module and the BCU to clear any error codes and reinitialize the system settings.
  • Test System Functionality: Following the reset, test the upper worklights to ensure they receive sufficient power and illuminate correctly. Continue to monitor the system to ensure no further issues with current delivery.
  • Regular Maintenance and Checks: Include regular checks of the vehicle’s electrical system in the maintenance routine to prevent similar issues in the future. Routine inspections can help catch potential problems early, preventing downtime and ensuring safe operations.


Regular maintenance of the vehicle’s electrical systems is crucial for ensuring safe and efficient operation. Ensuring that all components, especially those critical for safety such as lighting, are regularly inspected and maintained helps prevent issues like open circuits and ensures that machinery performs optimally under all conditions.