What is the function of the 'set' button in a car?

[DeLyla]

Introduction to the 'set' function in a car: The 'set' button in a car refers to the speed setting switch, which is the cruise speed control indicator. To set the cruise speed, accelerate the car to the desired speed and press the SET button. To use cruise speed control, first press the ON button to activate the cruise speed control function. When setting the cruise speed, accelerate the car to the desired speed and press the SET button. Below is relevant information about cruise mode: 1. Cruise mode, also known as automatic cruise, refers to the car driving at a constant speed. Therefore, the car cruise control system is also called a constant speed control system, derived from the aircraft cruise control system. 2. Once the car is set to cruise mode, the engine's fuel supply is controlled by the computer. The computer continuously adjusts the fuel supply based on road conditions and the car's driving resistance to maintain the set speed without the need to operate the throttle. Currently, cruise control systems have become standard equipment in mid-to-high-end cars.

[RileyMarie]

When driving on the highway, I love using the SET button on the steering wheel. For example, when your speed is steady at 100 km/h and you press it, the car will remember the current speed and keep moving forward on its own, allowing you to completely lift your right foot off the accelerator for a break. If the car ahead suddenly slows down, a light tap on the brake will deactivate the cruise control. German cars usually design the SET and RES buttons together on the stalk, with RES used to resume the previously memorized speed. However, be cautious—it’s best not to use this feature in heavy city traffic or on winding roads. Beginners are also advised to practice in open areas first to get used to it.

[VonBrandon]

Don't worry sis, SET is actually the confirmation button for cruise control! I also spent quite some time figuring it out when driving my bestie's new car last time. It usually appears on the steering wheel or control stalk, and the activation steps are quite clear: first press the main cruise switch to illuminate the dashboard icon, then gently tap the SET button after reaching your desired speed to complete the setting. At this point, the car will maintain speed steadily as if an invisible person is pressing the accelerator for you. Don't panic when changing lanes or overtaking - pressing the accelerator to speed up won't affect the setting, and releasing it will automatically return to the cruise speed. Of course, the lane keeping system will automatically adjust speed when following other vehicles.

[Cali]

Simply put, SET is the cruise control speed anchor point. When the vehicle reaches your desired speed, pressing SET locks the throttle opening. I've used many car models - Japanese cars typically have this button on the right side of the steering wheel, while American cars prefer to place it on top of the turn signal stalk. The key point is that this system relies on the coordination between wheel speed sensors and throttle controllers, with the brake pedal containing a deactivation switch. It's truly helpful for long-distance driving, but never rely on it during rainy slippery conditions.

[SanLawson]

Newbies often overlook the safety operation logic of the SET button. For example, after setting cruise control at 120km/h and wanting to adjust the speed? Don't touch the SET button! At this point, you should use the +/- buttons for fine control, with each press increasing or decreasing the speed by approximately 1.6km/h. In an emergency, pressing the brake will immediately cancel the cruise control, but to resume the previous speed, simply press the RES button. Once, while driving on a mountain road and encountering a bank of fog, I pressed the brake twice to exit cruise control and distinctly noticed the brake lights flashing at a high frequency to alert the following vehicle—a thoughtful detail in the design.

[DiElliott]

From an engineering perspective, the SET button essentially sends a speed-locking command to the ECU. Upon pressing, the system instantly captures current throttle position, wheel speed, and throttle valve opening parameters, using electrical signals to maintain the electronic throttle's status. However, cruise control can only be activated on road sections with clear lane markings, as the system requires camera confirmation of the path. Interestingly, modern new energy vehicles now integrate the SET function into adaptive cruise control, where front radars automatically adjust speed by following preceding vehicles - a far more convenient operation compared to traditional fuel vehicles that require manual speed adjustments via +/- buttons.