A Vintage Truck Third Brake Light Built with an ESP32

In 1986, the United States federal government started requiring that all passenger cars have a third brake light for safety — light trucks got the same requirement in 1994. The purpose of the requirement is, of course, to make your brake lights more visible. But not many vehicles had a third brake light before that requirement went into effect. That’s why Redditor Davepl used an ESP32 to add a third brake light to a vintage truck.

Davepl has this installed on a second generation GMC C10 pickup, but the setup should work on any pickup truck that is wired for pulling trailers. The ESP32 plugs into the trailer connector to pull accessory power and determine when the brake lights or turn signals are on. In turn, it controls a weatherproof strip of WS2812B individually-addressable RGB LEDs. Those can be set to light up in any color and with a variety of different effects, including starting with an attention-grabbing strobe before transitioning to solid illumination.

The code, which is loaded onto the ESP32 development board through the Arduino IDE, uses some clever programming to determine when the brake lights are on. It also can determine if the turn signals are on, and automatically syncs the LEDs to flash at the same time as they do. Davepl’s truck does already have a third brake light, so this isn’t really necessary. But the effects are cool, and it’s a great safety measure. If you replicate this, just be sure that the lighting colors and effects aren’t violating your local laws.