BCU 523691.12 – Current Detected When Lower Worklights on Cab Frame Are Off. John Deere System Advisory.

BCU 523691.12 (BCU )

Code: 523691.12



Error code BCU 523691.12 is triggered when the power module (HF) PC6 detects a current of more than 1 amp in lead 1034 to the lower worklights on the cab frame (E20/R and E20/L) or the xenon (HID) worklights on cab frame (E36/R and E36/L), despite these lights being switched off. This condition typically indicates a short in the electrical circuit or an internal fault within the power module itself, which could lead to unintended power consumption or potential damage.


The power module may isolate the affected circuit or maintain it in an error state to prevent any potential damage or further electrical issues, effectively disabling the worklights until the fault is resolved.


  • Inspect Wiring and Connectors: Thoroughly examine the wiring and connectors to the specified worklights for signs of damage, wear, or improper connections that might be causing the short.
  • Measure and Test Circuit Current: Use a multimeter to measure the current flow in the circuit when the lights are turned off to confirm the presence of unwanted current and help localize the fault.
  • Identify and Repair Short Circuits: Focus on identifying areas where shorts may have occurred, such as pinched wires or exposed conductors, and repair these faults.
  • Check and Replace Faulty Components: If the power module itself is suspected to be faulty, consider testing its components and replace if necessary to ensure it operates correctly.
  • Reset Systems and Confirm Resolution: After repairs, reset the affected systems and test thoroughly to ensure that no current flows when the worklights are off, confirming that the issue has been effectively resolved.


Continuous monitoring of electrical systems and quick response to fault codes like BCU 523691.12 are essential for maintaining the safety and efficiency of machinery operations. Regular maintenance can help prevent such issues by ensuring that all electrical components are in good condition and correctly functioning.