Ignition Interlock FAQs

Unless you’ve used one in the past or know someone who has, ignition interlock systems may be a bit of a mystery to you. Now, however, you could have a court order to install one in your car or you might just be thinking about one for personal reasons. Either way, the following FAQ should provide some relevant information.

What Is an Ignition Interlock?

An ignition interlock device is a machine that keeps your engine off until you’re able to register an acceptable BAC (Blood Alcohol Content) by blowing into a mouthpiece. There are three main components:

The handheld device which you blow into stays by the driver’s seat.

The cord that runs to your ignition, where the relay is either closed or opened.

The attachment to your engine.

How Do I Know They Work?

In most states, certification is required before an ignition interlock device can be used for court-appointed purposes. The National Highway Traffic Safety Administration also has standards they’ve established for this market.

How Will the Device Affect My Car?

The short answer is that it won’t have any permanent effects on your car. Installation is a very simple procedure. Your approved mechanic will simply disconnect some wires from your engine and replace them with the new ones that connect to your ignition interlock device.

You may want to use Velcro to keep the handheld portion of the machine close to your steering wheel, but even that can be easily removed later.

Having one of these devices installed will also have absolutely no impact on your vehicle’s warranty.

What Happens if I Fail?

Your car will not start until you blow an acceptable BAC. With most devices, one fail is not a big deal (you may have just had mouthwash), but you’ll have to wait a minute or two before you can blow again. If you think it was something like mouthwash or a piece of gum, be sure to wash your mouth out thoroughly before trying again.

There are also rolling tests you’ll have to take though. This is when you’ll be asked to breathe into the machine while you’re driving. If you fail one of these, your vehicle’s lights will begin flashing and your horn will sound until you pull over and shut it off.

Can These Machines Be Tricked?

Today’s ignition interlock devices are so sophisticated that they are basically impossible to fool. For example, you could hotwire the vehicle, but the machine would register that it had been turned on without a breath and would immediately demand one.

Some people have even tried using the air from a balloon (or some other source) to trick the machines into recording a clean sample. However, modern anti-circumvention technology is able to detect artificial breath.

The only thing that would work would be having someone else blow for you. This is a great way to get in a lot of legal trouble though.

Hopefully, the above has helped answer most of your ignition interlock questions. Like we mentioned above, if you have any others, be sure to ask the manufacturer.