How to Check and Test Your Garage Door Sensors

Published Date: Oct 31, 2025

Dealing with a garage door not closing can be frustrating — and there are several possible causes to consider. One of the first things worth checking is your garage door safety sensors. These small devices are easy to overlook but play a major role in the system’s safe operation. In this guide, we’ll walk you through how to check garage door sensors, test them, fix common problems, and know when it’s time to bring in a pro. Homeowners, property managers, and contractors alike can save time and money by following these steps. And if things still don’t work? Up & Down Garage Doors has your back with expert service.

Step 1. Check for Visible Sensor Issues

The first step in garage door sensor troubleshooting is a visual inspection.

Here’s what to look for:

Make sure the sensors are clean — dust or cobwebs can block the beam.
Confirm the lights are on. One sensor should have a steady green light, the other amber.
Check for any signs of physical damage to the sensors or wiring.

If the lights are off or blinking and cleaning doesn’t help, the sensors could be worn out or faulty. To help you decide, here’s a helpful guide on when to replace garage door sensors.

Step 2. Run a Quick Sensor Safety Test

Once they look fine, it's time to test them. Testing garage door safety sensors is quick and tells you if they’re actually working.

Try this:

Open the door fully
Place a lightweight object (like a broom or cardboard box) in the sensor path
Press the button to close the door

If the door reverses immediately, your sensors are working. If it doesn’t, alignment could be the issue. Follow this easy guide on how to align garage door sensors to realign them safely.

Step 3. Troubleshoot Garage Sensor Problems

Still having issues? Let’s go deeper with garage door sensor troubleshooting. These are the most common fixes homeowners can try:

Misalignment: Even a small bump can throw the beam off. Adjust the sensors until both lights are solid.
Sunlight interference: Bright sunlight hitting the lens can break the signal. Shade it and try again.
Loose wires: Gently push the wire connections to see if anything is loose.

If you’ve tried these fixes and your garage door still won’t close, check out our full garage door sensor troubleshooting guide for more details on common sensor issues and how to fix them.

Step 4. Check Other Causes for a Garage Door Not Closing

If your sensors are clean, aligned, and passing the safety test, but the door still won’t close — then the issue might lie elsewhere.

In some cases, the problem is with the opener itself. Older openers can fail to process sensor signals or stop responding reliably. If your opener is making strange noises, hesitating, or behaving inconsistently, it could be time for a new garage door opener.

Step 5. Garage Door Still Stuck? Call Up & Down Garage Doors

Sometimes, no amount of cleaning or adjusting solves the problem. If you’ve gone through these steps and your garage door still isn’t working, it’s best to call in a professional.

The team at Up & Down Garage Doors has years of experience diagnosing and fixing issues just like this. From faulty sensors to wiring problems or full opener replacements — we’ve seen it all.

Don’t wait for the issue to get worse. Book trusted garage door repair services with Up & Down Garage Doors today and get back to safe, smooth operation.

FAQs: Garage Door Sensor Troubleshooting

How do I know if my garage door sensors are bad?

If the lights are off or blinking and the door won’t close, your sensors may be damaged or misaligned.

What’s the first thing to try when garage door sensors don’t work?

Start by cleaning the lenses and checking for visible alignment and solid lights on both sensors.

Why is my garage door not closing all the way?

Misaligned or blocked sensors are common causes. Other times, the opener may be the issue.

Can I fix garage door sensors myself?

Yes, most fixes like cleaning and adjusting alignment are easy and safe for homeowners.

When should I call a professional for garage door sensor troubleshooting?

If you’ve checked alignment, cleaned the sensors, and tested them — and the door still won’t close — it’s time to call a technician.

Boxes everywhere, bikes leaned against the wall — you’re mid-garage cleanout when you hit Close. The door starts down, pops back up, and the opener’s status light starts flashing. That’s classic photo-eye behavior: the two little sensors near the floor (one sender, one receiver) lost alignment. Before you touch brackets or start guessing, try a quick garage door sensor reset — a safe power cycle that often clears a momentary glitch on the opener’s logic board. In this guide, Up & Down Garage Doors explains how to reset garage door sensors the right way, what each LED pattern means, and when a simple reboot turns into an alignment or wiring fix.

How to Bypass the Garage Door Sensors: Causes & Fixes

A nor’easter knocks out power on your block, the opener reboots, and your photo-eye sensors blink out of sync. The door starts to close, then snaps back up, leaving your tools on display. Often, that’s a misaligned or obstructed photo-eye safety sensor. While you might want a quick workaround, learning how to bypass the garage door sensors should be treated as a one-time, emergency step to get the door closed. Federal safety standards, such as UL 325, require these sensors to prevent entrapment. This guide from Up & Down Garage Doors explains the temporary override and why a permanent repair is the only safe long-term solution.

Garage Door Motion Sensor Security Features

A garage door serves as more than just a means of entry. The security system in your house depends on it. The unsung heroes of its many functions are motion sensors, which provide convenience and safety levels. When this sensor breaks, your garage door can pose a danger to both users and those nearby. Up & Down Garage Doors is a professional garage door company in CT, committed to ensuring safe and precise installations and maintenance. We share our experience to give you a quick solution that is based on proven methods and offer our services to give you a safer dependable solution for your garage door needs since we recognize that trying to fix complex problems yourself can create more issues. In this article, we will explore how garage door motion sensors work and how to troubleshoot some basic issues with this part of your garage door system. Let’s dive in!