How to fix your ADT motion sensor

You’re upstairs taking an afternoon power nap, when you hear your BFF calling out from downstairs. You knew they were planning on stopping by at some point, but your ADT sensor didn’t trigger an alarm upon them coming in. Then it dawns on you: your device isn’t working.

No need to fret. We can help you get back up and running. At Asurion, taking care of you and your tech is what we do best — including educating you on the ins and outs of smart home security systems. Here’s how to fix an ADT sensor that's not working.

Common ADT motion sensor problems

Even the best-maintained ADT sensor can run into a few hiccups every now and then.

Blinking red light on motion sensor

Just because you’ve noticed an ADT motion detector red light doesn't mean it's an immediate cause of concern. It’s probably in walk test mode. The system typically enters this state when it’s newly installed or immediately after getting new batteries. The purpose? To allow you to test and verify the sensor’s detection range and functionality.

But if you own an old ADT motion sensor and it starts blinking red, it’s likely a hardware issue.

Motion sensor not detecting movement

This problem can be a big headache for any homeowner, but it can usually be addressed. When a sensor fails to detect movement completely, it’s usually due to interference, incorrect placement, or possible disconnection.

Low battery alerts on ADT sensors

How often do you swap out your ADT’s battery for a new one? That could explain the ADT motion sensor flashing red patterns. When ignored, a battery-starved sensor could consistently trigger false alarms or, worse, fail to detect movement altogether.

How to troubleshoot ADT motion sensors

Sleep better at night with these quick fixes for troublesome ADT sensors.

Replacing batteries and resetting the sensor

If you suspect your sensor is ailing from a connectivity or power issue, start by replacing the lithium batteries. Wait a minute or two, then give it a good old system reboot. It’s easier and faster when you do it from your control panel.

Checking sensor alignment and position

If you recently moved your sensor or corresponding magnet, intentionally or not, you may have impeded its detection power. To realign the system, mount it at a height of 8 feet or so while facing the intended area. Angling matters as well.

Addressing issues with old sensor models

No luck yet? Another fix to try, especially for those with older models: purchase a new sensor. Outdated sensors are notorious for being incompatible with newer software and triggering false alarms. When upgrading, make sure you’re buying the sensor from a certified provider or through ADT.

While you're at it, why don’t you take a look at our guide on the best smart home security systems to protect your home?

Adjusting sensor sensitivity for false alarms

Some motion detectors trigger way too easily. Things like pets and passing shadows shouldn’t be setting off your alarm. So, if that’s your issue, consider adjusting the sensitivity settings via the ADT control panel diagnostics. If “pet immunity” mode isn’t enabled already, enable it to cut out the nuisance without compromising security.