How to Fix a Garage Door Sensor

A garage door sensor is designed to keep your garage door from closing should any object interrupt the beam going from the light transmitter to the receiving sensor. A garage door sensor that is functioning erratically or not at all is a hazard that you need to fix immediately.

The methods for fixing the sensor are similar regardless of make, and they require supplies from a hardware store and tools common to most households.

Fix Faulty Wire Connection

  1. Loosen the screws on the side of the sensor receiver using a Phillips screwdriver. Unwind the two wires from around the screws.

  2. Scrape the exposed ends of each wire with the blade of a utility knife until the copper is shiny.

  3. Shake a can of electrical cleaning spray for five seconds. Spray each screw with a two-second burst to remove contaminants that are inhibiting a good connection to the wires.

  4. Wind the ends of the wires around the screws. Tighten the screws. Blow off the plastic front of the sensor with a burst of compressed air.

Remove Obstructions

  1. Place your head along the edge of the sensor transmitter that is at one end of the garage door.

  2. Draw an imaginary line to the receiving sensor at the other side of the garage door.

  3. Remove any objects that are to the side of either sensor along the imaginary line.

  4. Remove any objects that are beneath the imaginary line that could interfere with the beam -- for example, loose leaves on the garage floor’s gutter grille.

  5. Sweep the area inside the garage on one side of the sensors, using a broom. Sweep the area on the side of the sensors on the outside of the garage door, using a broom.

Adjust Sensor Height

  1. Measure the height from the floor to the garage door sensor transmitter and to the receiving sensor, using a tape measure.

  2. Measure 6 six inches up from both sensors with the tape measure if either or both of them are less than 6 inches from the floor. Make an “X” at this point on the sides of the garage door’s frame with a pencil.

  3. Remove the screws from both sensors using a Phillips screwdriver.

  4. Realign the sensors up to the “X” mark.

  5. Reattach the screws through the sensors and into the sides of the garage with the screwdriver at the “X” marks.

  6. Tip

    Shut off the garage door opener with its power switch or by cutting the power at the fuse box prior to fixing a problem with the sensor.