Which pin on a 7-way plug provides the power supply for the electronic control unit (ECU)?

The correct answer pertains to the functionality of the pins within a 7-way plug used for towing connections. In towing systems, the electronic control unit (ECU) often requires a dedicated power supply to operate. Pin 3, which is typically designated as the blue wire in this configuration, is responsible for providing this power supply.

The ECU in a towing setup manages various electronic features like braking and stabilizing systems. It is crucial that this unit receives sufficient power for its operation to ensure safety and efficiency while towing. Therefore, Pin 3 serves the important purpose of delivering power from the towing vehicle to the ECU, allowing it to function properly.

Understanding the roles of other pins can enhance your knowledge; for instance, the other pins have different functionalities, such as lighting and braking signals, which are essential in their own right, but do not provide power to the ECU. This distinction is key in ensuring that the towing setup operates safely and effectively.