ASE Brakes Certification Practice Exam 2025 – Complete Study Resource

In the context of a stop light system where the lights are always illuminated, a short to ground is least likely to be the cause of this symptom. The basic operation of stop lights involves a brake switch that completes the circuit when the brake pedal is pressed, allowing current to flow and illuminate the lights. If there was a short to ground, it would typically cause the stop lights to remain off, as the circuit would be bypassed to ground without energizing the lights.

On the other hand, a defective brake switch can fail in a manner that keeps the circuit closed even when the brake pedal is not pressed, thus keeping the lights on. A short to power could also create a situation where the lights are illuminated continuously as it feeds direct power to the lights without regard to switch activity. Likewise, a misadjusted brake pedal may result in the brake switch being engaged even when the pedal is not pressed, which would also keep the lights on.

Therefore, among the options presented, a short to ground is the least likely scenario for causing the stop lights to be perpetually illuminated, making it the correct choice in this diagnosis.