What is the SET function in a car?

[MirandaAnn]

SET stands for the speed setting switch. It is the cruise speed control indicator. When setting the cruise speed, accelerate the car to the desired speed and press the [SET] button. At this point, the car speed usually needs to be greater than 30 miles per hour (approximately 48 kilometers per hour). When using cruise speed control, if you step on the brake, the cruise speed control will stop working. Here is some relevant information: 1. The cruise control system mainly consists of a command switch, sensors, ECU, and an actuator. 2. The ECU has two input signals: one is the command speed signal set by the driver as required, and the other is the feedback signal of the actual driving speed. After detecting the error between these two input signals, the controller generates a throttle control signal sent to the throttle actuator, so that the throttle actuator adjusts the throttle opening of the engine according to the throttle control signal to correct the error detected by the electronic control device, thereby keeping the speed constant.

[ReedDella]

I used to frequently use the SET button during long-distance drives, mainly for the car's cruise control function. Simply put, when you accelerate to your desired steady speed on the highway, pressing the SET button on the steering wheel allows the car to remember that speed and maintain it automatically, eliminating the need to keep your foot on the accelerator. This saved me a lot of effort, especially during five- or six-hour drives. For example, I often drive from the city to the countryside—once on the highway, I press SET to lock in 80 km/h, and the car maintains that speed steadily, giving my feet a break. However, this isn’t autonomous driving; you still need to steer manually. In special conditions like rain or winding roads, I manually cancel it using the CANCEL button to interrupt or the RESUME button to return to the previous speed. Some newer models also use the SET button for tire pressure monitoring—after adjusting the pressure, pressing it confirms the settings to avoid constant alerts. But in most cars, cruise control remains the primary function of SET. Over time, it feels like a thoughtful design, though it’s important not to rely on it too much for safety.

[MacDaniella]

Let's talk about the SET button. Its core function is to set the cruise control speed. While driving, accelerate to your desired speed, say 100km/h, then press the SET button near the steering wheel. The system will lock this speed, allowing the car to maintain it automatically. I often explain this when teaching driving—it frees your right foot, especially useful on highways, but never use it in urban areas or complex environments as it can distract and cause accidents. Related buttons include CANCEL to pause and RESUME to continue, with intuitive logic: after setting the speed, it's easy to pause and resume later. Safety-wise, I've emphasized repeatedly that cruise control isn't foolproof; it must be used only on straight, clear roads and turned off immediately in rain or snow. By the way, modern vehicles may extend SET to instrument settings, like adjusting screen brightness and then pressing SET to save, but speed cruise remains fundamental—mastering it enhances the driving experience.

[Sanders]

At first, I didn't know what the car's set button was for, but later I understood it's a setup button bound to cruise control. After accelerating to, say, 90km/h, pressing set makes the system remember that speed, and the car automatically maintains it. I tried it during my driving lessons—it's quite convenient on highways, eliminating the need to constantly press the accelerator. However, you must be cautious; this feature shouldn't be used in areas with frequent lane changes or during rain. If it feels unsafe, press cancel to pause it. Simply put, it's a tool to help you maintain a preset speed.