Automotive Service Excellence (ASE) A6 Electrical/Electronic SystemsLighting Systems Diagnosis and RepairEasy
A vehicle's left turn signal flashes rapidly, but the right turn signal operates normally. All other lights function correctly. What is the most probable cause?
- AA short circuit in the left turn signal wiring
- BA faulty turn signal flasher relay
- CA burnt-out left front or left rear turn signal bulb
- DAn open circuit in the right turn signal wiring
Show answer & explanationAnswer & explanation
Correct answer: C. A burnt-out left front or left rear turn signal bulb
A rapid flash rate for a turn signal is a common indicator that one of the bulbs in that specific circuit (either front or rear) is burnt out or has an open circuit, reducing the total current draw and causing the flasher to operate faster.
Why the other options are wrong
- A. A short circuit would typically blow a fuse or prevent the turn signal from working at all, not cause a rapid flash.
- B. A faulty flasher relay would likely affect both turn signals or cause no flash at all, not just one side.
- D. An open circuit in the right turn signal wiring would affect the right side, not the left, and would likely result in no flash on the right side.
Hyper-flashing
A rapid flashing rate of a turn signal indicating a burnt-out bulb or reduced load in that circuit.
- Caused by reduced current draw due to a missing/burnt bulb.
- A diagnostic feature of turn signal flashers.
- Check all bulbs on the affected side.
Memory trick: Fast blink, bulb's brink!