BCU 523919.12 – Inner Worklights on Front of Roof Off, Current Detected. John Deere System Advisory.

BCU 523919.12 (BCU )

Code: 523919.12



Diagnostic trouble code BCU 523919.12 is triggered when the power module PC0 detects a current of more than 1 amp in lead 1046, even though the inner worklights on the front of the roof (E18/1) are switched off. This condition typically indicates a short in the circuit or an internal fault within the power module itself, which could potentially lead to overheating, electrical damage, or fire risk.


The system’s response to this issue may include activating current overload protection to prevent further electrical damage. Additionally, an alert may be issued to the operator, signaling the need for immediate inspection and maintenance to address the electrical fault.


  • Inspect Wiring and Connectors: Thoroughly examine the wiring and connectors associated with lead 1046. Look for signs of damage such as fraying, corrosion, or loose connections that might cause a short circuit.
  • Test for Short to Ground: Use a multimeter to test the circuit for continuity and locate any potential short to ground. Focus on identifying specific locations where shorting may occur.
  • Replace or Repair Damaged Components: If specific areas of damage or malfunction are identified, replace or repair the faulty wiring or components to resolve the short circuit issue.
  • Check Power Module Integrity: Ensure that the power module PC0 itself is not the source of the fault. If the module is damaged, it may require testing or replacement.
  • Reset and Test the System: After repairs are made, reset any associated fault codes and test the system to ensure that the issue has been resolved and that the current remains within safe operational limits.


Regular maintenance and proactive checks of the vehicle’s electrical systems are essential for identifying and rectifying issues such as shorts and unexpected current conditions. Early detection and correction of electrical faults help maintain the safety and efficiency of operations, thereby extending the life of the equipment. Addressing such issues promptly is key to minimizing downtime and ensuring that the lighting system remains operational and effective.

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