What To Expect When You Install A Car Breathalyzer

Life changes when you have a driving under the influence (DUI) conviction on record. You spend hours arranging court dates, hundreds of dollars paying fines, and you may need to install a car breathalyzer or ignition interlock in your vehicle. Although you can’t change your conviction, you can ease the transition and successfully complete your interlock device program if you know what to expect from the beginning.

How Does A Car Breathalyzer Work?

An ignition interlock or car breathalyzer prevents drunk drivers from driving their vehicle. The device is connected to your vehicle, and it has a preset level for blood alcohol concentration (BAC) determined by your state. This is typically very low, so any alcohol or even using alcohol containing products can cause a test failure.  If you blow into it when you are over the set limit, your vehicle won’t start.

All car breathalyzers must meet or exceed both local and state regulations as well as National Highway Traffic Safety Administration (NHTSA) standards. If your car breathalyzer detects alcohol above the limit, your interlock device will lock your vehicle for a period of time determined by your state – usually between 5 to 30 minutes. Once that time has passed, you can test again. If you fail the test once more, the device will lock your vehicle down for a longer period of time.

What happens if you fail a rolling retest?

If your state requires it, you may be asked to blow into your car breathalyzer when your vehicle is in motion or for a ‘rolling retest’. If you fail the rolling retest, your vehicle will sound its alarm or horn and lights will flash until you pull over and turn off the engine. IT WILL NOT SHUT THE CAR OFF.   Instead, you will need to pull over to a safe location when you can, turn off your vehicle and re-test to re-start it.

The Guardian Interlock is small, compact, and easy to use, and although it looks like a simple device, there is software built in to prevent cheating the ignition interlock. When you blow into your car breathalyzer, all information will be sent wirelessly to the court on a weekly or daily basis.

When you have an interlock installed, you will need to make adjustments to your daily routines.  The first 30 days are usually the most difficult.  As one of our customers reviewed, “Larry the installer was courteous, knowledgeable and efficient. After installation he demonstrated how to use the interlock. It seems to be sensitive to air pressure used and ‘hum quality’, what ever that is. Don’t be in a hurry and keep and eye out for prompts to blow while you drive. Good luck.”


  1. Is there a device that could be installed just for personal use as a safety feature before any violation occurs? For example, for a personal vehicle that has teen drivers.

  2. Charles Hickman says:

    Yes – ignition interlocks can be installed voluntarily in many states. Please give a call to 800-499-0994 and a representative will help you out. Thank you for contacting Guardian.

  3. Kelvin Cressey says:

    what is the cost of these ignition interlocks

  4. Charles Hickman says:

    The cost varies by state, due to state regulations. Give Guardian Interlock a call at 800-499-0994 and a representative will be happy to give you the rates for your area.

  5. What’s the cost in Ohio?

  6. How would the lock know it’s your breath. Could someone breathe In it for you and pass?

  7. Hi guys
    I’m all the way from South Africa looking to perhaps run your product nationally , we have a terrible record with drinking & driving which results in hundreds of deaths a year .I’m inspired to change this stat. , I’m a co owner of two audio stores where our installation experience should be enough to install your product after some training.
    How can I get started with importing your product down to see if I can indeed install them and if they are compatible with most cars.

    Looking forward to hearing your response


  8. Would this be a good device for someone you know who has drank and drove and my be an alcoholic? Would it prevent them from drinking and driving?

  9. Charles Hickman says:

    You can get more information about becoming a Guardian provider at https://guardianinterlock.com/about-us/guardian-provider/

  10. Charles Hickman says:

    Please call Guardian Interlock at 800-499-0994 and they’ll be happy to quote rates and answer your questions.

  11. Charles Hickman says:
  12. Charles Hickman says:

    The devices prevent anyone who has been drinking from getting behind the wheel and driving.

  13. William de dios says:

    Can you. Get another diw if you blow and fell

  14. Charles Hickman says:

    That will depend on your state’s laws and the ignition interlock program in your state. Check with an attorney, a probation officer, or call Guardian at 800-499-0994 to speak with a representative.

  15. Gina higgins says:

    Need pricing for monthly fee and installation Cost for my dad s dodge ram 2007 Truck in Austin Texas

  16. Charles Hickman says:

    The fastest way to get pricing and an installation appointment is to call Guardian Customer Service at 800 499-0994. Thank you for contacting Guardian Interlock.

  17. Can anyone use your car without blow starting, what if the car is being repaired?

  18. Are they put on every vehicle that’s in your name

  19. Anonymous says:

    A friend told me mot to use mouthwash before using the auto breathalyzer. Is this true?

  20. Editorial Staff says:

    Certain products have alcohol in them, including many mouth wash products. It is best to always rinse your mouth with water prior to taking any and all tests.

  21. Editorial Staff says:

    To have any vehicle work completed with an interlock in your car, you will want to contact Customer Support at 800-499-0994 to obtain a mechanic affidavit. This form allows mechanics the ability to work on the car and gives them overrides to avoid testing while they service the car.

  22. Editorial Staff says:

    Correct! Mouthwash usually contains alcohol and will result in a false positive reading. It is best to rinse your mouth with water before taking a test. It is also important to know that many other food and household items contain trace amounts of alcohol and can result in a false positive test. When you first start to use your interlock, you will need to make minor changes to your routines to ensure that your breath samples are alcohol free. If you usually brush your teeth, hop in the car with your coffee and drive to work these things can all interfere with a proper breath sample. Instead, bring water with you, give yourself some extra time to allow the device to warm up and take your test. Skip the coffee, cigarettes or vaping while you are driving and need to take the rolling re tests. We know changes like this are difficult in addition to getting used to the device, but following these guidelines will help you successfully complete your program.

  23. Editorial Staff says:

    There are anti-tampering features built into the device. Our devices comply with national and state standards which require anti circumvention technology.

  24. Editorial Staff says:

    Anyone who uses the car must also use the device. In some states, it’s ok for people other than the person ordered to have the interlock use the vehicle, but they must test and re test while driving. If your car is needing repair, call our contact center at 800-499-0994. You will need to fill out a “Mechanic’s Affidavit” prior to having the vehicle serviced. This is submitted to your monitoring authority and enables us to give an override code to the mechanic so they can complete the work on your vehicle without using the interlock. It’s very important that the monitoring authority be notified properly so that your reporting is correct.

  25. Editorial Staff says:

    Hi! It depends on the state. For example, Iowa requires every vehicle (even motorcycles) that are registered in your name be equipped with an interlock if you are required to have one. Washington State only requires them on vehicles you drive. Check you state’s regulations for clarification, these can usually be found on the state licensing agency’s web site.

Speak Your Mind