Garage Door Lift Sensor Dead...or is it he door lift itself?

[GGD]

Could possibly be the wiring between the sensors and the motor unit. Often that wiring is exposed and can get yanked when moving stuff in the garage near the sensors, or chewed on by rodents.

Also make sure that nothing is blocking the path between the two sensors, like a broom, rake, or rags.

Also, what happens when you try to lower the door? With my unit, if it's blocked by the sensor, the light bulb in the main unit will flash on and off quickly.