Description:

The error code, ATC 523979.07, is triggered when the control unit receives the engagement signal from the heated rear window switch (S139, lead 2013) for an extended period of time. This condition usually suggests that the switch is either jammed or defective, or there is an underlying issue in the circuit such as a stuck button, short, or wiring problem that keeps the circuit closed.

Reaction:

The fault can lead to continuous operation or non-operation of the heated rear window, potentially causing it to remain on indefinitely or fail to activate when needed. This could affect visibility through the rear window under certain conditions.

Recommendations:

• Inspect the Switch and Associated Wiring: Examine the heated rear window switch (S139) and its connections, particularly at lead 2013, for signs of physical damage, wear, or corrosion that could contribute to a jam or fault.
• Test the Switch Functionality: Use diagnostic tools to test the switch function, checking for consistent performance and ensuring it toggles on and off correctly.
• Replace the Faulty Switch: If the switch is found to be jammed or defective, replace it with a new unit to restore proper functionality.
• Check Circuit Continuity: Use a multimeter to check the continuity and integrity of the circuit, looking for any shorts or open circuits that could be causing the issue.
• Verify System Operation After Repair: Once the switch and any associated components have been repaired or replaced, test the system to ensure the heated rear window operates as intended and that the issue has been resolved.

Note:

Ensuring that switches and controls for vehicle functions are in good working order is essential for reliable operation. Regular maintenance checks and prompt repairs or replacements of faulty components help prevent minor issues from escalating into more significant problems, thereby maintaining the vehicle’s functionality and safety features.