How to Replace the Safety Sensor for a Garage Door Opener


GDO Safety Sensor_881024812

The safety sensor prevents the garage door from closing on an object. The sensor has one photoelectric eye that sends an infrared beam and another that receives it. If an object breaks the beam, the closing door reverses direction. When a safety sensor fails, the remote won't work and the lights on the motor unit blink when you press the remote. To test the sensor, connect the photo eyes directly to the motor unit with short wires. Hold the eyes close together, facing each other. If it's defective, follow these steps on how to fix your garage door sensor using a manufacturer-approved replacement part.

Repair difficulty:
Time required:

Less than 15 min.

Parts Required

  • Safety sensor kit for a garage door opener

For manuals, repair guides, and specific part recommendations, enter your model number.

Tools Required

  • Pliers
  • Wire cutters
  • Blue wire nuts (if crimp wire nuts aren't included)
  • Ladder
  • Safety glasses
  • Work gloves

Before you begin

Wear work gloves and safety glasses.



 Warning: Undertaking repairs to appliances can be hazardous. Use the proper tools and safety equipment noted in the guide and follow all instructions. Do not proceed until you are confident that you understand all of the steps and are capable of completing the repair. Some repairs should only be performed by a qualified technician.

Step 1: Disconnect the power

Unplug the garage door opener from the wall outlet. 

Step 2: Remove the sensor

Remove the wing nut from the safety sensor.

Pull the sensor from the bracket.

Cut the wires about an inch from the safety sensor, leaving enough slack to connect the new sensor.

If the safety sensor kit didn’t come with a crimp wire nut, strip 1/2" of insulation from the ends of the wires. 

Step 3: Connect the new safety sensor

Separate the control wires on the new sensor. If the safety sensor didn’t come with crimp wire nuts, strip 1/2" of insulation from the ends.

Connect the black-striped control wire to the black-striped wire on the new safety sensor. If crimp wire nuts didn’t come with the safety sensor kit, twist a blue wire nut to secure the connection.

Connect the solid white wires the same way. 

Step 4: Install the new safety sensor

Slide each new photoelectric eye into its bracket and secure it with the wing nut.

Step 5: Line up the photoelectric eyes

Plug in the motor unit of the garage door opener. Adjust the safety sensor's photoelectric eyes so the indicator lights on the sending eye and receiving eye glow steadily. 

Step 6: Test the safety sensor

Open the garage door completely. Place a box or similar object between the sending and receiving eyes so it's obviously in the path of the beam.

Use a remote to close the garage door. The door shouldn't move more than an inch before it stops and then reverses, and the lights on the motor unit blink.

If the safety sensor doesn’t pass this test, have the garage door opener serviced.