Does the third brake light stay on with lights on on a 2003 Nissan Frontier?

Yes, on a 2003 Nissan Frontier, the third brake light should illuminate when the headlights are turned on, but it will only stay on when the brake pedal is pressed. This behavior is standard for most vehicles, as the third brake light is designed to signal braking rather than simply being a running light. If the light remains on without the brake pedal being engaged, it may indicate a wiring issue or a faulty switch.