If your garage door refuses to close, the culprit can be something as small as a sensor problem. Garage door safety sensors are designed to prevent the door from closing on people, pets, or objects. They’re an important safety feature — but when they stop working, you can find yourself stuck with a door that won’t move.
The good news? Many sensor problems are easy to diagnose and fix. We’ll walk you through common causes, how to spot a bad sensor, and when to call in a pro.
Why Is My Garage Door Sensor Not Working?
Garage door sensors use an invisible infrared beam to detect obstacles. If the beam is blocked or interrupted, the door won’t close. Common causes include:
- Dirt, dust, or spiderwebs on the lenses.
- Objects in the path of the beam (even something small).
- Misalignment due to vibration, accidental bumps, or loose mounting brackets.
- Direct sunlight interference hitting the receiving sensor.
- Wiring issues such as frays, corrosion, or loose connections.
Start with the easy fixes — clean, clear, and align — before assuming the worst.
How Do You Know if a Sensor Is Bad?
Not every sensor issue means the sensor itself is bad — sometimes it’s just dirty or misaligned. However, you may have a bad sensor if:
- The LED light on one or both sensors is off completely.
- The light blinks even after you’ve cleaned and realigned the sensor.
- The door refuses to close no matter what you try.
You can test by swapping the sensors (if your system allows) or by consulting your opener’s manual for diagnostic codes. If the same side continues to fail after swapping, it’s likely the sensor is defective.
Should Both Garage Sensors Be Green?
On most garage door opener models, one sensor (the transmitter) will have an amber or red light, and the other (the receiver) will show a green light when everything’s working correctly.
- Solid lights on both = sensors are aligned and communicating.
- Blinking light = misalignment or obstruction.
- No light = possible wiring issue or bad sensor.
Check your brand’s manual for color variations — LiftMaster, Raynor, and Chamberlain models may have slightly different light colors.
Common Causes of Garage Door Sensor Problems
Even a tiny misalignment can keep your garage door from closing. The most frequent issues are:
- Obstructions in the path — toys, tools, or debris.
- Dirty lenses — dust, pollen, or bugs.
- Misaligned sensors — the brackets may need to be adjusted so both sensors point directly at each other.
- Wiring problems — wear, corrosion, or disconnection.
- Sunlight interference — bright light hitting the receiver sensor can trick it into thinking something’s in the way.
How to Fix Garage Door Sensor Problems
Here’s a simple troubleshooting process:
1. Clear the Path
Even a small leaf, tool handle, or child’s toy can interrupt the invisible beam. Make it a habit to keep the area around your garage door tracks clear.
2. Clean the Lenses
Dirt, dust, cobwebs, or even moisture can block the beam between sensors. Use a soft microfiber cloth to wipe the lenses gently. Avoid using harsh chemicals, which can damage the lens coating.
3. Realign the Sensors
Garage door sensors must face each other directly to function. If they’re knocked out of place by a broom, car bumper, the beam can break. Loosen the mounting bracket screw slightly, adjust until both sensor indicator lights are solid (no flicker), re-tighten.
4. Inspect the Wiring
Over time, wires leading to the sensors can become loose, frayed, or chewed by rodents. Inspect where the wires enter the back of each sensor and trace them back to the opener.
5. Reduce Sunlight Glare
If sunlight is the problem, try shading the sensor with a small cover or adjusting its angle slightly.
Deciphering Sensor Lights & Patterns
Your sensors’ LED lights are your first clue:
- Solid light = aligned and working.
- Blinking light = alignment problem.
- No light = no power or bad sensor.
When to Call a Professional
If you’ve cleaned, realigned, and checked the wiring but your door still won’t close, it’s time to bring in a garage door technician.
Call a pro immediately if:
- The sensor lights won’t turn on.
- The wiring is damaged.
- You’re uncomfortable working around electrical components.
If your overhead door won’t close because of sensor issues, it’s time to look into a garage door repair expert. A technician can test the sensors, replace defective parts, and make sure the opener is running safe and smooth. Trust their expert knowledge to provide you with peace of mind.
Bottom line: Garage door sensor issues are often quick to fix if you know what to look for. Start with cleaning, alignment, and checking for obstructions — and if those don’t work, a professional can get you back up and running fast. Our team provides same-day service to evaluate, and fix the problem quickly and correctly.