Start with the sensors
- Look at both sensor lights near the floor on each side of the door. Both should be steady.
- Clean the lenses with a soft cloth.
- Check alignment. Bump the bracket gently until both lights are steady. A sensor knocked by a bike or bin is the most common cause.
- Check the wires running up the wall and to the opener. Staples, lawn equipment and pests damage them.
- Check for sunlight shining straight into a sensor, especially in winter with low sun.
If the sensors are fine
The opener may be flashing a diagnostic code. Newer LiftMaster and Chamberlain units show codes with an LED near the learn button or on the light. Write down the number of flashes and look up your model on the Chamberlain Group support site. Common causes include a wiring short, a travel-limit problem or a motor or logic-board fault.
Repair or replace the opener?
- Sensor or wire fault: a small repair.
- Logic board or gear kit on an older opener: compare the repair ($85 – $225 on published Long Island prices) with a new opener ($250 – $875).
- No battery backup, loud chain drive, no Wi-Fi: a new opener may be worth it anyway.
More: garage door opener repair and installation.
Don’t bypass the sensors
The sensors are part of the federally required entrapment protection on residential openers (16 CFR Part 1211). Taping them together or removing them stops the door from reversing when something is underneath.
Need it done? Call for garage door opener repair & installation on Long Island. Local guides: garage door repair in Dix Hills, garage door repair in Smithtown.
Frequently asked questions
My LiftMaster light blinks 10 times. What does that mean?
On LiftMaster and Chamberlain openers, the lights flashing 10 times when you try to close the door is the standard sign of a safety sensor problem: misaligned, blocked or a wiring fault.
Why is the light on my opener's motor blinking even when the door is closed?
Some openers use a blinking LED or light to show a diagnostic code, a lock mode, or a battery-backup issue. Check the model's manual or the manufacturer's support site for that model's codes.
Can I replace garage door sensors myself?
Sensors are low-voltage and some owners do replace them. Getting them aligned and making sure the auto-reverse works afterward is the important part.