Inspect each sensor to make sure the green or red power indicator lights are.
Garage door sensor will not light.
If one or both of the lights are off check the fuses breakers and plugs for problems.
Check the mechanism s source and sensor leds.
If both the red source and green sensor lights are on and not blinking then the door mechanism is working properly.
Raise the garage door using the control button on the garage wall or the remote control unit from a vehicle.
If you see that the sender sensor is not yellow and the receiver sensor is not green then this means that your sensors are probably off.
If your garage door randomly doesn t close and the light blinks you may have a failing sensor.
If you own a garage door opener by lift master chamberlain or craftsman you ll notice that the sender sensor will usually shine a yellow light and the receiver sensor will usually shine a green light.
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.
When the safety sensor is not properly aligned or something is obstructing the light beam the garage door will fail to close.
These sensors are little black boxes found on either side of the bottom of the garage door.
The liftmaster garage door opener lights will flash for ten times.
You ll need to first equip yourself with a wrench of some sort and a tape measure.
So how do you fix this issue.
If you find the lights turned off in one or both the sensors it indicates that there is a problem in power supply.
One will have a green light used to show that the units are powered up and the other will have a red light to show that there s no obstruction between the sensors and that they re seeing each other.
Each sensor will usually have a light.
For the door to close correctly without reversing the safety sensors need to be aligned perfectly and there should be nothing in the way of the light beam.
The garage door sensor yellow light and the green light together create a solid illumination.
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.