This guide walks you through how to align garage door sensors step by step, and when the problem calls for professional help. Your garage door starts to close, drops a few inches, then reverses right back up even though nothing is blocking it. That's the classic sign of misaligned sensors, and it's one of the most common garage door problems homeowners face. The fix is usually straightforward and takes about 15 minutes. This guide walks you through how garage door sensors wor