Yellow Light Flashing (10 flashes)
Chamberlain Garage Door Opener
Severity: ModerateWhat Does This Error Mean?
The Chamberlain opener flashing a yellow or amber light 10 times means the safety sensors are not aligned correctly — the door will not close until the sensors are fixed. Look at both sensor LEDs at the bottom of the door tracks. The green LED (receiving sensor) must be solid, not blinking.
Affected Models
- Chamberlain B970
- Chamberlain B6765
- Chamberlain B4505
- LiftMaster 8500
- LiftMaster 8580
- Chamberlain RJO70
Common Causes
- Safety sensor (photo eye) knocked out of alignment
- Something blocking the sensor beam path — cobweb, dirt, or an object
- Sun shining directly into the receiving sensor — overwhelming the beam
- Sensor wiring damaged or connector loose at the opener motor unit
- Sensor lens dirty
How to Fix It
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Locate the two sensors at the bottom of the door tracks.
The sensors sit approximately 4-6 inches above the floor on each side of the garage door opening. One sensor sends an infrared beam (amber LED); the other receives it (green LED). The door will not close if the green LED is blinking or off — the beam is broken or misaligned.
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Clear any obstructions from between the sensors.
Look between the two sensors for any object, dirt buildup, spider webs, or leaves blocking the beam path. Clear any obstruction and watch whether the green LED becomes solid.
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Realign the sensors.
The sensors are mounted on adjustable brackets held by wing nuts. Loosen the wing nut on the green (receiving) sensor. Slowly pivot the sensor until its green LED becomes solid and bright — this indicates perfect alignment. Retighten the wing nut gently without moving the sensor.
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Clean both sensor lenses.
Wipe both sensor lenses with a dry cloth. Dirt, oil, or water on the lens scatters the infrared beam and prevents a solid lock.
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Shield from direct sunlight if applicable.
In late afternoon in certain seasons, sunlight entering through the garage door can shine directly into the receiving sensor, blinding it. If misalignment occurs only at certain times of day, this is the cause. A small piece of cardboard taped above the sensor as a sunshade resolves the problem.
Frequently Asked Questions
Can I bypass the Chamberlain safety sensors?
The safety sensors are a mandatory federal safety requirement — they must be present and functioning for the door to close automatically. Bypassing them is illegal and creates a serious risk of injury to children, pets, and adults. Do not attempt to bypass or disconnect the sensors. If the sensors are damaged, replace them.
My Chamberlain sensors are aligned and the green LED is solid, but the door still will not close — why?
If both sensor LEDs are solid and correct (amber sending, solid green receiving) but the door still will not close, the sensor wiring may have a fault — a wire break or loose connector at the motor head. Check the wiring running from each sensor up the door track to the motor unit, and confirm both white and white-with-black-stripe wires are securely connected.