ASE G1 Auto Maintenance and Light RepairElectrical/Electronic SystemsMedium
A technician is diagnosing a vehicle with a complaint of intermittent headlight operation. Both headlights sometimes flicker or go out completely, but then return to normal. The battery and charging system test within specifications. Which of the following is the MOST likely cause?
- AA faulty headlight switch.
- BAn open circuit in the headlight wiring.
- CA short circuit in the headlight wiring.
- DA single burned-out headlight bulb.
Show answer & explanationAnswer & explanation
Correct answer: A. A faulty headlight switch.
Intermittent issues affecting both headlights, especially flickering or complete loss followed by restoration, often point to a common component that controls both, such as the headlight switch, which may have worn or dirty internal contacts.
Why the other options are wrong
- B. An open circuit would cause a complete and continuous loss of power, not an intermittent flickering or return to normal.
- C. A short circuit would typically blow a fuse or trip a circuit breaker, leading to a continuous loss of power or no operation, not intermittent flickering.
- D. A single burned-out bulb would only affect one headlight, not both, and would not typically cause flickering.
Intermittent Headlight Faults
Headlights that sporadically flicker or cease operation and then resume, often indicating a problem with a shared control component like the headlight switch or a loose connection.
- Affects both headlights (usually).
- Sporadic flickering or complete loss/return.
- Often points to a control component or loose connection.
Memory trick: Flicker, flicker, where's the common link in the light's dance?