A blinking photo-eye light usually means the safety circuit cannot confirm a clear path. The cause may be an object, moved bracket, dirty lens, damaged wire or failed sensor.
Clear the beam path first
Remove stored objects, tools, leaves and debris from the opening. Check that nothing crosses the line between the two sensors near the floor.
Do not tape the sensors together, move them above their intended position or bypass the circuit.
Compare both indicator lights
Depending on the opener model, one sensor may show power while the other confirms alignment. A dark, blinking or inconsistent light can help distinguish alignment from wiring or power problems.
Small bracket movement matters
A bumped bracket, vibration or a loose fastener can move the photo eye just enough to interrupt communication. Wiring can also be pinched, corroded or loose at the sensor or opener head.
The door may also be resisting
If the sensor lights appear normal but the door still reverses, check for a repeated bind, damaged roller, track obstruction or travel-setting problem. Sensor symptoms and mechanical resistance should not be confused.