Turn Signals: Your Car’s Overlooked Alert System
Turn signals are an integral component of any automobile, able to alert other drivers of your intent and ultimately prevent collisions, injuries, and fatalities. However, these devices are sorely unappreciated and what may seem like a simple lever which activates a flashing light is actually a complicated mechanism.
In this article, I’ll explain the mechanics behind your car’s indicator lights. We’ll explore what is happening behind the scenes that causes them to activate. You’ll also learn how they’re disengaged by turning your steering wheel.
The Circuitry Behind The Lights
It’s important to note that the circuit which controls your vehicle’s indicators is only operational when your car is turned on. The electrical power flows to the turn signal flasher which then directs the current to either the right or left indicator depending upon the position of the signal stalk.
When the current is flowing, the thermal flasher generates the light pulses via heat expansion. The thermal flasher is composed of the electrical contact that feeds electricity to the wire, a piece of curved spring steel. It also feeds electricity to a secondary piece of spring steel wrapped in a resistive wire. Initially, the current flows through the secondary wire wrapped with the resistive wire which proceeds to heat up and expand, eventually touching the contact.
Once it is connected to the contact point, the light is triggered and the resistive wire begins to cool down. With the secondary spring cool, it begins to contract, pulling and separating the connection and thereby disengaging the lights.
How They Are Reset
When the turn indicators are activated, a small plastic tab engages with the main steering column via a notched hub. This notched hub (connected to the steering wheel) secures the plastic tab until the wheel is turned. When the steering wheel is rotated, the plastic tab is continuously bumped in one direction until you turn in the opposite direction to compensate. When the steering is reversed, the tab is forced out of its position and the turn-signal stalk returns to normal.
Side Mirror Signals
Unfortunately, turn indicators are fallible; they can malfunction if the circuit dies or the electric current is severed from the wires. For this reason, many car companies have started using LED lights embedded in the side mirrors. These systems use LEDs that are arranged in an arrow formation and are placed behind the mirror so your sight isn’t impaired when using them.
These LED lights are also useful because they are able to light up much faster than a traditional incandescent bulb. This may seem insignificant at slow speeds, but when traveling on the freeway, a few tenths of a second can literally mean the difference between life and death.
Find more car tips at Cars Like Us and Car Part Plus
