Electrical 101

Troubleshoot Garage Door Opener

Garage door openers are used for opening a garage door automatically, using a wireless or wired controller. The wired controller is usually located outside of the garage door and/or near the entrance to the house from the garage. Newer homes usually have the wiring installed for openers or may already have an opener installed.

Garage Door Opener Wiring

Garage door openers use an outlet in the ceiling for power. The wired controller and sensors use low voltage wiring (usually 24V) to connect to the motor unit.

Garage Door Opener Sensors

Garage door openers use “safety reversing sensors” to prevent the door from closing if a child, pet, or any object is under the door.

These sensors are mounted close to the ground on each side of the garage door entrance. One of the sensors, the sending eye, transmits a focused beam of light to the receiving eye. When there is no obstruction to the sensor beam, the garage door is allowed to close. When something obstructs the beam of light, the garage door should immediately return to the full open position.

During installation the sending eye and receiving eye are aligned so the beam of light from the sending eye shines on the receiving eye.

Garage Door Opener Won’t Close

There are two common reasons a garage door opener won’t close.

Sensor not working properly
Opener has failed

Garage Door Sensor Problems

There are a few reasons why an opener sensor may not be working properly. Sensors usually have indicator lights to show their status.

The sending eye indicator light shows it has power from the opener unit. The receiving eye indicator light shows if it is aligned properly with the sending eye.

Here are things to check before calling an opener repair person.

Look for spider webs over the sensors.
Check for proper sensor alignment. Someone may have accidentally bumped one of the sensors out of alignment.
Check for loose wire connections on the motor unit.
Check for loose wire connections near the sensors.

Since the sensors use low voltage, sometimes the wires are improperly connected near the sensors. Some installers may twist the wires together and use electrical tape to cover them (image above right). If a connection like this fails, it should be reconnected with wire connectors. Small blue or gray twist connectors work well.

Garage Door Remote Not Working

After inspecting the battery compartment for corrosion, replace the batteries. If that does not fix it, try the other remote (if you have one). PhoneData Wire Butt Connectors If it still does not work, the remote or receiver in the motor unit may have failed.

The image to the right is connected wires using phone data butt splice wire connectors.

While working properly, if the beam of light does not shine on the receiving eye, the door won’t close. If the door is closing and the beam is interrupted, the door should stop closing and return to the open position. The photo at left is a receiving eye sensor. To tell which sensor is the sending eye or receiving eye, place a hand in between the sensors. Blocking the beam with your hand should turn off the indicator light of the receiving eye. Both sensors have a wing nut for alignment with the other eye.

Improperly connected wires

Properly connected wires using twist wire connectors