A fundamental element of car operation, the purpose of the car switch is to interrupt an electrical circuit or to establish it (in case it is closed).

Car switch: the main types of switches

The housing of a car switch incorporates electrical contacts at its input and output, whose connection depends on the position of a switch operated by the driver.

While the basic principle is simplistic, the switch can take many forms and offer multiple functions.

On/Off switch

This is the most straightforward switch described in the previous paragraph: simultaneously opening and closing one or more circuits.

For example, the circuit breaker found on some vans and motor homes controls the general power supply to the battery or the overhead light switch. 

The push button

Unlike the classic switch, it does not establish a constant closing of the circuit: when the operator stops his action, it returns to its resting position of opening the circuit.

Some examples: the horn, the headlights call…

The multifunction switch

Typical in cars, the light switch or the windshield wiper switch is a complex switch combining the control of several circuits (high beam, low beam, position lights, direction indicators, fog lights, etc.).

These circuits can be controlled:

• independently (headlights and turn signals);
• simultaneously (position lights and headlights);
• alternately (high beam and low beam).

It is specific to each type of vehicle and can integrate other functions, such as powering lights on the dashboard or controlling the onboard computer.

The pulse switch

It works like a push button: the driver’s brief action causes a momentary change in the circuit’s voltage.

This impulse is transmitted to a computer or control box, which switches the circuit by the action of a relay (= switch controlled by an electromagnetic coil, powered either by an action of the driver such as the control of the headlights or by automatic control, with the actuation of the cooling fan by the temperature sensor of the engine) and powers an electrical device.

The best-known application is the impulse control of vehicle windows.

Maintenance of the car switch

The car switch is a critical element of the electrical circuits weakened by the miniaturization of its contacts. It is one of the first elements checked in case of malfunction, especially since it is often accessible.

Depending on its complexity, its control can be:

• Quick and straightforward using a shunt (= electrical wire placed at the input and output of the switch, short-circuiting its action) such as the brake contactor;
• Very complex, requiring a multimeter, a confirmed technical level and a thorough knowledge of the vehicle’s electrical architecture (the steering wheel switches are the most difficult and involve multiplexed circuits on modern vehicles (= communication system allowing the circulation of various information between computers).

Replacing a switch

Replacing a basic switch will involve a few difficulties for the majority and a derisory cost. On the other hand, a complex switch such as a steering wheel switch will most of the time require a professional’s intervention to repair multiplexed systems.

Where to go for reliable auto electrical services in Melbourne?

ROBUST AUTO ELECTRICS delivers a variety of auto electrical services. They can work on vehicles of all makes and models and ensure your electrical systems work as efficiently as possible.

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