BCU 523691.04 – Excessive Current in Lower Worklights on Cab Frame. John Deere System Advisory.

BCU 523691.04 (BCU )

Code: 523691.04



Error code BCU 523691.04 occurs when the power module (HF) PC6 detects a current exceeding 15 amps in lead 1034, which services the lower worklights on the cab frame (E20 or E36), when these lights are activated. This high current measurement typically indicates a short to ground within the circuit, posing a risk of damage or fire if not addressed promptly.


To protect the system and prevent potential damage, the power module will likely disable the affected worklights and possibly activate a fault mode to alert the operator to the issue.


  • Inspect Circuit for Short to Ground: Carefully examine the wiring and components in the circuit for any signs of damage, wear, or exposure that could cause a short to ground. Focus particularly on areas where insulation might be compromised.
  • Test Electrical Components: Use electrical testing tools to measure resistance and continuity in the circuit. This helps pinpoint exactly where the short is occurring.
  • Replace Damaged Wiring or Components: If specific damaged components or sections of wiring are identified, replace them to eliminate the short to ground.
  • Ensure Proper Circuit Load: Verify that the circuit load does not exceed the recommended limits, and adjust or replace components as necessary to comply with specifications.
  • Reset and Test the System: After repairs, reset the power module and test the worklights and circuit to ensure that the issue has been resolved and the current remains within safe operating limits.


Regular monitoring and maintenance of electrical circuits are critical, especially in systems that handle significant loads like worklights. Immediate attention to any signs of overcurrent can prevent more severe issues and ensure both safety and functional reliability of the equipment.