Garage Door Goes Down Then Back Up Liftmaster

If your Liftmaster garage door goes down then back up, there are a few possible causes. The most common cause is a problem with the sensors that detect when the door is closed. These sensors are located on either side of the door, and they emit a beam of light. When the door is closed, the beams of light are interrupted, and the door stops closing. If one of the sensors is blocked or misaligned, the door may think that it is still open and will start to go back up.

Another possible cause of this problem is a fault with the logic board. The logic board is the brain of the garage door opener, and it controls all of the functions of the door. If the logic board is damaged, it may send incorrect signals to the door, causing it to go down then back up.

Finally, a problem with the wiring can also cause this problem. If the wires that connect the sensors to the logic board are damaged, the door may not receive the correct signals from the sensors. This can cause the door to go down then back up.

If you are experiencing this problem, there are a few things you can do to try to troubleshoot it.

Check the sensors. Make sure that they are not blocked or misaligned. You can do this by manually closing the door and seeing if the sensors light up. If one of the sensors does not light up, it is likely blocked or misaligned.
Check the wiring. Make sure that the wires that connect the sensors to the logic board are not damaged. You can do this by visually inspecting the wires for any cuts or breaks.
Reset the logic board. You can do this by unplugging the garage door opener from the power outlet and then plugging it back in. This will reset the logic board and may fix the problem.

If you have tried all of these troubleshooting steps and the problem persists, you may need to contact a qualified technician to repair the garage door opener.