What does it mean when your garage door sensor is flashing red?

When your garage door sensor is flashing red, it is trying to tell you there is a specific fault that needs attention, and the meaning changes slightly by brand. On a Genie garage door system, a flashing red light on the sending sensor most often means there is a wiring problem, a short circuit, or the sensor has lost stable power from the opener motor head. It can also indicate the sensor itself has failed internally and cannot produce a steady beam. On LiftMaster, Chamberlain, or Craftsman openers, you typically do not have a red light on the safety sensors themselves, so if you see a flashing red, you might actually be looking at the opener's learn button or the wall control diagnostic light, not the safety eye. In general, any flashing light on a garage door safety sensor means it is not in its normal solid state. For the receiving sensor, flashing usually means misalignment, dirty lens, direct sunlight interference, or a physical obstruction breaking the invisible beam. For the sending sensor, flashing usually means a power or wiring issue. You should start by cleaning the lenses, checking alignment, and inspecting the wires for damage.