How to Test & Troubleshoot Garage Door Opener Sensors

Any residential automatic garage door opener manufactured after 1993 will not travel downward without a functioning automatic safety reverse mechanism, which means your garage can be left vulnerable to theft and intruders if your opener sensors malfunction. It’s important to test your garage opener sensors to ensure they are in proper working order to catch any indication of trouble before your door is unusable. Action Direct has handled garage door sensors for decades, and below we’ve listed how to test your sensors as well as possible problems and fixes in case of a malfunction.

Why Are Garage Door Opener Sensors Necessary

Federal law requires that all residential automatic garage door openers manufactured after January 1, 1993, must be equipped with safety reverse sensors. This important safety feature is designed to protect your family and pets from accidental injury or death due to entrapment. It works by automatically reversing the direction of the closing garage door in the event that it makes contact with a person or object in its travel path.

How to Test Your Automatic Safety Reverse Sensors

Testing your automatic safety reverse sensors is an easy task to perform once a month. It costs nothing, only takes a moment to complete, and helps to ensure the overall safety and health of your automatic garage door opener system. Follow these simple steps to test your garage door's automatic safety reverse sensors:

Place an object such as a brick on the ground directly in the path of the door.
Activate the garage door opener to close the door on the object.
The door should automatically reverse when it makes contact with or senses the object in its path.
If the door does not automatically reverse, additional troubleshooting may be necessary.

How to Troubleshoot Your Garage Door Opener Sensor

If you experience difficulty with any of the steps in the testing process, there could be a range of issues with your sensor, and most are easy fixes. Malfunctioning sensors could be a result of a faulty power supply, sunlight interference, dirty lenses, faulty wiring, or misaligned sensors.

Faulty Power Supply

A garage door opener’s sensors can run into issues if its power supply is not functioning properly.

How to Fix a Faulty Power Supply

Check that the power supply is in good condition to ensure the problem lies in the sensor itself.

Sunlight Interference

The lenses on a garage door sensor rely on an infrared beam to detect if there is an object in the door’s way, and direct sunlight can potentially interfere with the infrared beam.

How to Fix Sunlight Interference

Check that your garage door opener sensors are not in direct sunlight. If they are, shield them from the sun. You can use small pieces of cardboard, purchase a sun shield, or move the sensor to a better location.

Dirty Lenses

Lenses can malfunction if they become dirty from dust or debris over time.

How to Fix Dirty Lenses

Clean the sensor lenses using a soft cloth. If debris remains, use a slightly moist cloth to gently wipe away any excess dirt.

Wiring Issues

Wiring problems such as a disconnected wire, poor connections, or a shorted wire can cause the safety reverse mechanism to fail.

How to Fix Wiring Issues

Wires are generally color-coded to match terminals. On Chamberlain, LiftMaster, Sears, and Raynor openers:
White wires connect to the white terminal.
Black and white wires connect to the gray terminal.
On Genie openers, wires can go to either terminal.

To test for a shorted wire:

Disconnect the sensors from the brackets.
Cut or disconnect wires about 12 inches from each sensor.
Strip the wires and twist matching colors together to the motor wires.
Unfasten wires from the operator terminals and reconnect them by color.
Aim the sensors at each other. If LED lights turn on, the wiring is the issue and must be replaced.
If LEDs do not light up, replace the sensors.
If lights still do not turn on, replace the logic board.

What to Do If Your Wires Need to Be Replaced

If your opener’s sensor wires are damaged, hire a professional electrician. DIY repair can risk injury or worsen the issue.

Misaligned Sensors

If the LED lights on your sensors are flashing, they may be misaligned or there could be an obstruction.

How to Fix Garage Door Opener Sensors

This is a simple DIY project with the right tools:

Gloves
Screwdriver
String
Beam level

Steps to align the sensors:

Shut Off the Power

Trip the breaker that powers the garage or unplug the sensors. Wear gloves when working with wires.

Loosen Screws on Sensor Mounts

Find the sensor brackets and loosen the side screws to allow movement.

Shift the Mounting Bracket

Slide each sensor down to its lowest possible position without detaching it completely.

Attach the String

Tie a string from one sensor across to the other, positioned across the center of the sensor lens.

Level Your String

Use a beam level to ensure the string is level. Adjust brackets upward if needed.

Fasten the Screws

Tighten the screws. Re-check the string with the level to ensure it remains level.

Turn the Power Back On

Remove the string and restore power. Test the sensors. If misalignment was the issue, they should now function correctly.

What to Do If Garage Opener Sensors Still Do Not Work

If none of the above steps fix the problem, refer to your owner’s manual or contact a garage door service professional. A technician can help diagnose the issue and provide the necessary repairs or replacement parts.

Need More Information on Garage Door Sensors?

Action Direct prides itself on quality customer service and providing complete product information. Our in-house experts are happy to help. Get in touch with our support crew.