Why is one of my garage door sensors yellow instead of green?

One of your garage door sensors is yellow instead of green because that is normal operation by design, as garage door safety sensors use different colors to distinguish sending and receiving functions. In most modern LiftMaster, Chamberlain, Craftsman, and Chamberlain systems, the sending sensor that emits infrared beam shows a steady yellow or amber LED when it has power, while the receiving sensor that detects beam shows steady green LED when it is aligned and receiving beam. So having one yellow and one green with both LEDs steady indicates sensors are properly aligned and working correctly, not a problem. The yellow sensor is typically on same side as wall button wiring, and green on opposite side. If yellow is steady and green is steady, door should close normally. If yellow is steady but green is blinking, off, or flickering, receiving sensor not receiving beam due to misalignment, dirty lens, obstruction, or wiring issue, causing door to reverse. If yellow is off, sending sensor has no power due to wiring break or bad sensor. Some brands like Genie use red for sender and green for receiver, or both green on older models, but yellow and green is standard for LiftMaster. Therefore, seeing one yellow and one green steady is correct and not cause for concern. If door reverses despite steady yellow and green, check close force settings, track binding, or travel limits, as reversal may be due to friction triggering auto reverse rather than sensor color.