How to Replace a Garage Door Opener Safety Sensor


GDO Safety Sensor_881024812

This DIY repair guide explains how to replace a safety sensor on a garage door opener. The garage door opener has two sensors that prevent the garage door from closing on a person or object: one that sends an infrared beam and one that receives the beam. If an object or person is in the way of the beam, the closing door reverses direction. If a safety sensor stops working, the remote control won't work and the motor unit lights blink when you press the remote.

Our garage door opener safety sensor troubleshooting video can help you confirm a problem with the safety sensor. If you determine the safety sensors have failed, replace the sensors using the manufacturer-approved replacement part.

Follow the steps in this repair guide and video to replace safety sensors in Craftsman, Chamberlain, LiftMaster and Genie garage door openers.

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)
  • Safety glasses
  • Work gloves
  • Step ladder

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.

How to replace the safety sensor for a garage door opener.

Step 1: Disconnect the power

Use a step ladder to access the garage door opener’s power cord and motor unit.

Unplug the garage door opener.

Step 2: Remove the sensors

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 in the control wire to connect the new sensor.

Repeat the process for the other safety sensor.


Step 3: Connect the new safety sensor wires

Separate the control wires on the new sensor.

Connect the black-striped control wire to the black-striped safety sensor wire using the crimp wire nut.

Connect the solid white wires the same way.

Repeat the process for the other safety sensor.


 Tip: If you're not using the crimp wire nuts that come with the new safety sensors, strip 1/2-inch of insulation from each wire and connect the wires using wire nuts.

Step 4: Install the new safety sensors

Slide the safety sensor into its bracket and secure it with the wire nut.

Repeat the process for the other safety sensor.

Step 5: Reconnect electrical power

Plug in the garage door opener.

Step 6: Line up the safety sensors

Align the safety sensors so the green indicator light on the receiving sensor glows steadily.

Step 7: Test the safety sensor

Open the garage door.


Place a box or similar object between the safety sensors to block the sensing beam.


Attempt to close the garage door using a remote.


The door should stay open and the motor unit lights should blink.


If the garage door opener closes the door with the safety sensors blocked, replace the logic board.