3rd Brake Light Bulb Replacement on a 2025 GMC Sierra 3500 HD Pro 6.6L V8 FlexFuel

The center brake light on your 2025 GMC Sierra 3500 HD, which is sometimes referred to as the third brake light or stoplight is also known as the center high mount stop lamp (CHMSL). The 3rd brake lights up when you hit the brake pedal and helps prevent you from being rear ended by the cars behind you. See how to change the center brake light (CBL) on your GMC Sierra 3500 HD in this how-to video. Be careful not to touch the bulb directly with your fingers when you replace the center brake light bulb on your Sierra 3500 HD, touching the bulb causes the it to burn out quicker.

A burnt out center brake light bulb in your Sierra 3500 HD is an excuse for a police officer to pull you over. Check your bulbs frequently and change burnt bulbs promptly. Sometimes the stoplight has multiple bulbs in the housing whereas in other vehicles, the 3rd brake light is an LED brake light strip that must be replaced all at once.