There is a significant amount of confusion between the different stages of the process for ignition interlock installation. A large amount of this confusion exists at the point where a court order for installation of an alcohol ignition interlock is given to a defendant and a compliant vehicle is supplied. For attorneys, for probation officers, and for fleet managers, it is very helpful to understand the problems at each of the interlock installation’s stages and where problems occur most frequently.
Booking the appointment and confirming eligibility
Installation typically is done by an approved Service Provider in your state, and not all service providers are approved in every state. Thus, work done by an unapproved service provider may not be acceptable to your court or to the monitoring authority in your state even if installed in your state.
The following documentation is typically required at the time of installation for a DUI interlock service provider, (1) a copy of the court order or license restriction; (2) a copy of the driver’s identification; (3) documentation of the vehicle on which the device is to be installed including the year, make and model and whether or not the driver is the owner of the vehicle. If the driver is not the owner of the vehicle, a signed consent to installation form must be completed by the owner.
Questions worth resolving before the vehicle arrives
- Does the order specify a camera, GPS reporting, or real-time violation alerts, and does the quoted device include them?
- Will the driver operate more than one vehicle, and does the jurisdiction permit a single device or require one per vehicle?
- Is a hybrid, push-to-start, or diesel vehicle involved, since these require specific wiring approaches and sometimes a different handset?
- Has the reporting calendar been established, and does the first service date fall inside the compliance window?
Preparing the vehicle so the appointment holds
A working battery is required for the power drawn by an interlock from the ignition circuit of a vehicle. All Interlocks rely on the electrical system of the vehicle to provide accurate readings. Interlocks have been known to pick up electrical interference caused by remote control car alarms, charge up indicators for cell phones, parasitic drain from an aftermarket stereo, and a variety of other factors that can cause a false reading in the data log. We typically try to address these kinds of problems before we leave an install.
When scheduling the installation of a DUI Ignition Interlock, clients should have sufficient fuel in their vehicle for the servicing, all keys to the vehicle, as well as any dash cams, or other accessories that may be installed in the vehicle. Also, if there are any known electrical problems with the vehicle prior to the installation, they should be repaired before the Ignition Interlock is installed to avoid costly repair to service monitored ignition circuits.
What happens during the installation
On average, an Ignition Interlock installation takes 1 1/2 to 3 hours. Typically, an Ignition Interlock is installed in the following locations, mounted in the driver’s seat; wiring connected to the ignition switch; wiring connected to a relay; Ignition Interlock control module connected; tamper seal applied to wiring connections; photographs of connections and vehicle’s current odometer reading taken; documentation sent to state agency authorizing installation and monitoring of Interlock.
The vehicle is then tested and calibrated for proper operation. For example, the technician tests to make sure that the starter is disabled prior to passing a breath sample and re-enabled afterwards. The interlock is also tested to ensure proper operation of a rolling retest while driving. Drivers working through a Southern California restriction are usually best served by booking DUI interlock installation in Los Angeles CA with a shop that issues this paperwork the same day. The technician documents all tests in the installation certificate that the client can carry to court or to the Department of Motor Vehicles to get plates re-issued.
Typical stages and timing
| Stage | Typical duration | What can delay it |
| Paperwork and identity verification | 15 to 30 minutes | Missing owner consent or court documentation |
| Wiring and mounting | 60 to 120 minutes | Aftermarket electronics, hybrid systems, corrosion |
| Calibration and function testing | 20 to 30 minutes | Low battery voltage, faulty ignition switch |
| Driver training and sign-off | 30 to 45 minutes | Language support needs, additional authorized drivers |
Device training and the first thirty days
When a device is being installed, the training given to the driver can sometimes be brief. He or she must learn to properly take a breath sample for the test. Many of the different types of interlock devices require a specific amount of air pressure to be put into the mouthpiece and can even make a ‘humming’ sound or require the driver to inhale after they have exhaled. If a sample is recorded as failing after such a training session, it is noted on the log as if the driver had intent to provide a failing sample.
Make sure the client knows the lockout rules (i.e. How long it takes to retest for a rolling retest, what a temporary lockout looks like and how to get a vehicle with a permanent lockout unlocked and running). Also make sure they know how to properly rinse their mouth with water and wait a few minutes before taking a retest sample to prevent a violation due to mouthwash, hand sanitizer, etc. Found near the mouthpiece of the igniter. Also tell them not to eat any unusual or “tasty” foods before coming in for testing (i.e. Garlic, fish, etc.) as these can get left in the airway and cause problems.
Ongoing servicing, reporting, and removal
How often does your client need to return for a service visit? Typically within 30 to 60 days depending on the state. Your install technician will download the data log, recalibrate the sensor(s) and inspect for tamper attempts on the required tamper seal areas of the device. The results of the service visit will then be uploaded to the state monitoring authority for review.
Practical monitoring points
- Track service dates independently rather than relying on provider reminders.
- Request copies of each data report so violations can be addressed before a review hearing.
- Confirm removal authorization in writing before scheduling the deinstallation, since early removal restarts the clock in many states.



