ATC 523979.05 – S139 Switch for Heated Rear Window, Current Too Low. John Deere System Advisory.

ATC 523979.05 (ATC )

Code: 523979.05



The error code, ATC 523979.05, is triggered when the control unit detects too low an amperage at the signal input of the indicator light in the heated rear window switch (S139, lead 2021). This condition often indicates an interruption in the circuit. For tractors without the optional heated rear window, this error might occur due to configuration issues or disconnected circuits meant for models with this feature.


The low current may result in the indicator light for the heated rear window switch failing to illuminate, which can lead to confusion about whether the rear window heating is active. This can affect the usability and functionality of the heated rear window feature.


  • Inspect Wiring and Connections: Check the wiring and connections at lead 2021 for any signs of damage, disconnection, or wear that could be causing the interruption.
  • Measure and Diagnose the Circuit: Use a multimeter to test for continuity in the circuit to locate any breaks or weak connections.
  • Repair or Replace Faulty Wiring: Repair any broken or disconnected wiring and replace damaged components to restore proper circuit integrity.
  • Configure System Settings: If the tractor is not equipped with a heated rear window but shows this error, verify system configuration and adjust settings or disconnect unnecessary circuits as required.
  • Test System Functionality: After repairs or adjustments, test the switch and indicator light to ensure they function correctly and display the active status of the rear window heater accurately.


Regular maintenance and inspection of electrical systems, especially those related to safety and comfort features like heated windows, are crucial for ensuring reliable operation. Proper management of system configurations during manufacturing and post-installation adjustments for specific features is essential to prevent erroneous fault codes and ensure that all vehicle functions operate as intended.