The LED or screen flashing indicates either "lock mode" or when the garage door openers internal system has traveled through a "passpoint".
When the garage door opener is in lock mode, the LED light on the door control will constantly flash and the hand held remote controls will not operate your garage door opener. The light bulb on the opener will also flash twice when you attempt to activate the door with your remote. To take the unit out of lock mode, press and hold the lock button for two seconds. Note: lock button may be located under push button cover.
If using a Smart Control Panel with screen display, the screen will show Lock Mode. If there is a lock button, press and hold the button for two seconds. If there is a menu button, press the button right under "off" on the screen. If the customer has a doorbell button, press and release the learn button, that will take the opener out of lock mode.
The hand held remote controls should now open and close the garage door.
The passpoint system is used to identify if the garage door opener is moving too slow, fast and to detect relative garage door position. Each time the garage door opener passes through one of the passpoints, the LED or screen will blink to indicate this. This feature can NOT be turned off, it is used to determine how many passpoints are being detected during a garage door openers cycle.