Depending on the brand of garage door you have one of the sensor lights may flash dim or go out completely when the beam is interrupted.
No sensor lights garage door.
First check the sensor lights.
Have no power to sensors neither sensor lights are on.
The wires from the terminal block on the opener to the door safety sensors should be connected to terminals 2 and 3 on the opener terminal block.
On line manual does not specify colors.
Check if the safety reversing sensors are aligned.
If the sensors are not.
Have adjusted several times.
Unlock the lock button if your door control has a lock button it may have been turned on.
Inspect each sensor to make sure the green or red power indicator lights are.
If you do not see a solid illumination or your garage door is not working the problem is most likely due to the sensors being out of line.
Look for small led lights on the sensors.
The lock button on the door control in on.
One wire from each sensor goes to terminal 2 and one wire to terminal 3.
If they re turned on in both the sensors then there is no issue with the power supply.
Safety sensors include two mounted sections one on each side of the garage door opening.
A common cause of a malfunctioning garage door sensor is lack of power supply.
Raise the garage door using the control button on the garage wall or the remote control unit from a vehicle.
Light doesn t activate on garage door opener when you cross safety sensor beam chamberlain group products which include the liftmaster chamberlain sears craftsman line of garage door openers have a feature where the opener light will turn on if you cross the safety sensor beam shooting across the opening of your garage door.
If you find the lights turned off in one or both the sensors it indicates that there is a problem in power supply.
It sounds like you have a broken wire to the sensor with the green led.
The garage door sensor yellow light and the green light together create a solid illumination.
For people who do not know the transmitter has the yellow light and the receiving sensor has the green light.