Inside Your Car 10 September 2022

Your guide to ignition switches

It’s Saturday morning, you’re running out the door, you put the key in the ignition… The engine struggles; it doesn’t start. Suddenly, all your plans for the day are out the window.

Ignition switches are a vital part of your car, so it’s good to know how they work, why they’re important, and the warning signs of a faulty ignition switch.

What is the ignition switch for?

The ignition switch performs a primary function in that it connects the circuit that provides voltage to your starter motor, allowing the engine to crank over and the engine to eventually start. In older vehicles it’s part of the key barrel, and you activate the ignition switch by turning the key. In newer, modern vehicles, you may be familiar with a ‘push button’ start, in which case, the ignition switch is activated by a computer in the vehicle, that closes the circuit and engages the starter motor.

In an older key barrel configuration there are 4 positions:

Lock - when your car is completely turned off.
Accessory - electrics that don’t use much power, such as your car radio, will work in this position.
On - this is the position your key will be in after cranking the engine and letting go of the key.
Start - this position cranks your engine and is spring loaded to go back to the ‘on’ position when the key is released.

In older key configuration ignition switches, failure is unlikely, with most key barrel configurations, reliable, and having no need for servicing. If your vehicle is much older, such as an EA, EB, or ED Falcon, your cause for intermittent no start, could very well be in the ignition switch assembly internally located in the key barrel.

What are the signs of a faulty ignition switch?

A faulty ignition switch can leave you stranded. To avoid this where possible, it’s good to know the warning signs.

Here’s what you should look out for:

Car won’t start: If your car doesn’t ‘click’ when you turn the key to crank the engine, the engine doesn’t turn over, and all the lights go out on the dashboard, it indicates an electrical problem that could be a faulty ignition switch or the ignition switch being ‘cut’ due to an immobiliser issue.

Can a faulty ignition switch drain your battery?

Absolutely although unlikely and the fault would be most likely on the ignition circuit, but in the key barrel assembly itself.

So before you go replacing the battery, in all cases whereby your vehicle presents with a no start concern, it’s best to have a qualified motor mechanic/technician investigate

What happens when the ignition switch goes out?

When an ignition switch fails, it is most likely due to wear on contact points, or faulty wiring.

The age of the switch—or poor quality parts—can also cause it to fail. Even a heavy keyring can cause problems over time, as the constant swaying and movement can cause wear on the cylinder and switch, eventually causing it to disconnect.

Problems with the ignition switch therefore happen gradually rather than suddenly, so any intermittent issues shouldn’t be ignored.

How long does it take to replace an ignition switch?

On average, it takes about an hour to an hour and a half to replace a faulty ignition switch, depending on the make and model of your car.

This is because even though the parts themselves are relatively simple, due to anti-theft devices, ignition switches are intentionally difficult to remove and replace.

How much should it cost to replace an ignition switch?

Because every car is different, , replacing an ignition switch including parts and labour, can vary between $150-$1500. It also depends largely on the type of anti-theft, immobiliser system the manufacturer has elected to use and whether or not you need keys cut and programmed, or re-programmed to the existing anti-theft module.

For peace of mind, it’s essential that you get your car checked out if your car’s been exhibiting any of the above issues.

Call mycar today to get your ignition switch inspected by one of our qualified mechanics at a workshop near you.