What Happens if You Fail a Breathalyzer During a DWI Stop?

 Posted on April 17, 2025 in DWI / DUI

Every case is different, but in general, if you fail a Breathalyzer test after being stopped for Driving While Intoxicated (DWI), that does not mean that you are definitively guilty. While it is evidence that the persecution will likely use against you, an experienced San Antonio DWI defense attorney may be able to challenge the test results.

How Can You Challenge a Failed Breath Test?

There are several defenses your lawyer may use to challenge a failed breath test admitted as evidence, including:

• Improper test administration: Texas has a procedure for administering a Breathalyzer test. Your attorney may challenge the validity if they find evidence of procedural violation, such as handling or storing the test incorrectly.

• Fourth Amendment rights violation: The officer who stopped you needed probable cause to administer the test. Without it, your representative could argue for suppression of the evidence on the grounds that they violated your Fourth Amendment rights.

• Missing informed consent: According to Texas’s implied consent law, driving constitutes consent to blood-alcohol testing for DWI. However, if the officer did not inform you of the consequences if you refused the test, you can argue that you did not provide informed consent.

During your initial conversation with your legal representative, it is important to explain what happened in the moments before, during, and after your arrest. These details will inform what defense is most appropriate in your case.

How Could a DWI Conviction Impact Your Life?

A DWI conviction is serious, affecting you financially and professionally. Your insurance company may increase your premiums, and you may need to get an ignition lock device for your car. It can hinder your career ambitions, rendering you ineligible for some professional licenses. For these reasons, seeking legal advice and representation is crucial.

How Can a Knowledgeable Attorney Help You?

A criminal defense lawyer with experience in Texas DWI cases will review the testing and arrest procedures and check the police report for mistakes made during the breath test and the arrest. They can check the test’s calibration and maintenance history and consult forensic and medical experts to understand how timing or any health condition you had when the arrest occurred could impact the test. If they find any holes in the evidence or protocol that invalidate the test, they can file a motion to suppress the results.

Speak With a San Antonio, TX DWI Defense Attorney Today

If you failed a breath test during a DWI stop, a San Antonio, Texas DWI defense lawyer at the Law Offices of Sam H. Lock is an asset in challenging your charges. You are presumed innocent until found guilty and have the right to a fair, robust defense. Call 210-226-0965 to schedule an initial consultation today and find out what we can do to protect you.