The turn signal switch performs several functions, both electrical, and mechanical, while indicating a vehicle turn. Electrically, it signals the turn signal flasher to flash either the right or left turn lights, both front and rear. Mechanically, it maintains the turn signal flasher function until the steering wheel is reversed from the turn direction selected. For example, if a left turn signal is selected, the turn signal switch will maintain a flashing left turn signal until the steering wheel is turned a certain amount counterclockwise (for a left turn), then turned clockwise back to a straight-ahead, or centered position. The same is true for a right turn. The flashing turn signal is then “cancelled”.
One of the most frequently used electrical components on a vehicle, a failed, or failing, turn signal switch may be indicated by the following symptoms:
1. Turn signal indicator continues to blink when the steering wheel returns to the center
This symptom likely reflects a failure of the mechanical portion of the turn signal switch. Unfortunately, we’ve all seen drivers cruising straight down the road, with their turn signal still blinking. This failure mode is the likely original cause.
2. Turn signal lights don’t continue flashing unless turn signal lever is held down
Similarly, this symptom also reflects a failure of the mechanical portion of the switch. Correction of this problem is best left to a YourMechanic professional mechanic who can provide you with a diagnosis, and then perform the turn signal switch replacement.
3. Left or right turn signals or the Hazard Warning Light not working properly
The hazard warning flasher and turn signal flasher functions are built into a single, integrated electrical unit, potentially affecting both turn signal and hazard flasher functions at the same time. A YourMechanic professional can confirm the hazard flasher failure, and replace the flasher unit if this is the failing component.
This article originally appeared on YourMechanic.com as Symptoms of a Bad or Failing Turn Signal Switch and was authored by David Wooten.