My chamberlain liftmaster garage door only opens when I hold wall button down until the end. the sensors are aligned but there the LED lights are not lit up on either side at all

Check sensor wiring for breaks or disconnection. Replace sensors which are available at Home Depot .

There could be a few reasons why you have to hold down the wall control button to close your garage door but the easiest one to rule out is misaligned safety sensors.
When you hold down the button on the control panel, you are overriding the safety feature and telling the opener no matter what is in the way just close the door.
Here are a few things to look for when checking the sensors:

1. Clean the sensor's lens and make sure dust, webs, and other debris is not obstructing the lens view.
2. If there are objects around the sensors that you move in an out of the garage (i.e. shovels in the winter, rakes in the summer) put them elsewhere. You may unknowingly hit the sensors and knock it out of alignment.
3.. Most, if not all, sensors have an indicator light that tells you they are functioning. One is usually green and one is red/orange. If one or both are not lit, adjust the sensors (one or both) until the lights come on. Then tightly fasten the bracket screw to make sure the sensors are secured in place.



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https://support.chamberlaingroup.com/s/article/How-To-Troubleshoot-The-Safety-Reversing-Sensors-When-Both-Leds-Are-Not-Lit