There is one main reason for failed interlock installations, cars that are not ready for them and/or people who are not ready to get them installed with the correct documentation to activate the RCM on the monitor’s account. An hour of preparation the week before will solve most of the problems.
Electrical condition decides whether the install holds
Because an ignition interlock constantly draws power (even when the engine is off), monitors for events (such as someone trying to hotwire the vehicle), and detects voltage drops, a weak or depleted battery will create ‘tamper events’ as well as power failures that are reported to the monitoring authority and provide evidence of the driver’s misconduct or neglect even if the driver did nothing wrong.
Prior to installation, have the battery load tested and verify the charger’s amperage. Clean corrosion from battery terminals, replace ground straps and look for any parasitic draw. Find out if the vehicle has aftermarket wiring, a remote start or a previous alarm system that was disconnected. Many wired installations have spliced connections that will need to be reworked by the interlock installer.
Checks worth completing in advance
- Battery load test and alternator output reading, documented with a printout where possible
- Starter and ignition switch function, since intermittent starting is often blamed on the device afterward
- Dashboard warning lights cleared or explained, particularly any that affect the engine control module
- Interior condition around the steering column and lower dash, where the handset cable is routed
- Windshield and cabin cleanliness, because mouthpieces and handsets are handled at every use
Vehicle eligibility and paperwork that gates activation
Each device has different vehicles it can be installed in and needs to be checked for compatibility by year, make, model and trim. Some hybrids, push-button starts, diesel engines with glow plug cycles and stop-start enabled vehicles have special wiring requirements and some manufacturers have certain restrictions on some of the installs that could affect your warranty if modified.
You also need proof of ownership and/or consent to install the interlock in a vehicle owned by another. If the paperwork is in order, a dealership service center works well, though drivers often get faster scheduling and clearer guidance from a shop that specializes in breathalyzer device installation Santa Maria drivers rely on for compliance work.
Stages of the program and what each one verifies
| Stage | Typical timing | What gets verified | Common failure point |
| Pre-install inspection | Same day, before wiring | Battery health, wiring integrity, vehicle compatibility | Weak battery or aftermarket wiring found on arrival |
| Installation and training | Two to three hours | Device function, blow pattern, rolling retest procedure | Driver leaves without practicing a retest |
| First service visit | Usually 30 days | Calibration, data download, early violation review | Missed appointment triggering lockout |
| Ongoing monitoring | Every 30 to 60 days | Accuracy drift, tamper logs, camera images | Unreported repairs or battery disconnection |
| Removal | End of restriction period | Final download, wiring restoration, compliance letter | Removing early without written authorization |
Keeping the service schedule from becoming a violation
Note that most interlock devices have a scheduled maintenance period that is pre-determined by the manufacturer and/or the monitoring authority. Such interlock devices will give the driver ample warning prior to the time that the interlock device will lock out the vehicle (usually several days). The lockout itself is reported as a non-compliance event whether the vehicle is left parked or not.
Practical scheduling habits
- Book the next service appointment while still at the counter for the current one
- Set a calendar reminder five days before the lockout date, not on it
- Notify the provider before any repair that involves disconnecting the battery
- Keep the service receipts and calibration certificates in the vehicle
Driver behavior after installation
Repeatability tests of mouth alcohol samples by an interlock are prompted at random intervals while a driver is operating a vehicle, and the driver is expected to safely pull over to a safe location on the side of the road or operate the vehicle until a test sample is provided while in motion as allowed by local statute. The reporting of a skipped retest by an interlock is a compliance event.
Products such as mouthwash, breath spray, some medications, energy drinks and even fresh bread can create positive readings due to residual mouth alcohol. A simple rinse of the mouth with water and waiting 15 minutes before taking a sample will prevent most of these false positives. All drivers of the vehicle must be made aware of these products and how they affect the Interlock readings for positive readings.
Confirm the rules that apply to your case
Note also that there are varying Device standards, Monitoring frequencies, Reporting thresholds, and Release of Interlock requirements throughout the various States and even within a single State depending upon the Specific Order imposed by the Licensing Authority, such as a Court or even Attorney at Law.
