SMART CONTROLLER: Designed with constant light, dimming, timer, and automatic switching functions. When the battery is connected, the daytime running lights will light up for about 45 seconds and then turn off. This is normal (implements the timer function). After that, you need to start the car. When the voltage reaches 13V+, it starts to work. WATERPROOF: The design is practical and durable. The high-quality ABS material makes it robust, corrosion-resistant, and durable. EASY INSTALLATION: 1. First, connect the positive and negative poles of the left and right daytime running lights, and then connect the negative poles. 2. Connect the red and black input wires to the controller's fuse to power the battery's positive and negative poles, and the red and black output poles to power the positive and negative poles of the daytime running lights. QUICK START: When the car is started (voltage must be above 13V+). The daytime running lights will automatically turn on during the day. When the headlights (or reading lights) are on, the daytime running lights will dim. When the car is turned off (voltage must be below 12.5V), the daytime running lights will turn off after 15 seconds.