Cost to Replace Garage Door Safety Sensors
Replacing a pair of garage door safety sensors (the photo-eye units near the floor) typically runs $85 to $200 for the parts-and-labor service call when a pro handles it, and the sensors themselves cost only about $15 to $50 a pair if you do it yourself. The good news: this is one of the more affordable garage door fixes, and a lot of the time the sensors aren't even broken — they're just knocked out of alignment or have a dirty lens, which costs nothing to fix.
Step by step
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1
First, rule out the free fixes before buying anything
Most 'bad sensor' calls turn out to be a misaligned or dirty sensor, not a dead one. Wipe both lenses with a soft dry cloth and check the little LED on each unit — one should be steady (the sending eye) and the other should be steady when aligned (the receiving eye). A blinking or dark LED usually means they're not pointed at each other. Gently nudge them until both glow solid. If that fixes it, you've spent $0.
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Confirm the sensors are actually the problem
With the LEDs lined up and lenses clean, try closing the door from the wall button (hold it down — that bypasses the sensors on most openers). If the door closes fine while held but reverses on its own otherwise, the sensors or their wiring are the culprit. Also check for a chewed or pinched wire near the bracket; rodents and lawn equipment are common offenders, and a $0 wire repair beats a new sensor.
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Buy the right replacement sensors
Garage door safety sensors are largely brand-specific. Match your opener brand — LiftMaster/Chamberlain/Craftsman often share the same sensors, while Genie, Linear, and Overhead Door use their own. A genuine pair runs about $30 to $50; universal aftermarket pairs can be $15 to $30. Bring your opener's model number (it's on the back of the motor unit) so you get a compatible set.
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Swap them out — it's mostly a wiring job
Unplug the opener first. Each sensor has two low-voltage wires (no shock risk, but play it safe). Loosen the wing nut on the bracket, unhook the old sensor, and transfer the wires to the new one — most use simple push-in or twist connectors with no polarity to worry about. Mount the new sensors at the same height on both sides, usually 4 to 6 inches off the floor.
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Align, then test the auto-reverse
Power back on and adjust each sensor until both LEDs glow steady. Then run the real safety test: place a roll of paper towels or a 2x4 flat in the door's path and hit close. The door must reverse the moment the beam is broken. If it doesn't reverse, do not use the door — the sensors aren't doing their job and need to be re-aligned or re-checked.
When to call a pro
Call a pro if you've cleaned and realigned the sensors and the door still won't close, if the wiring is frayed or chewed, or if you'd just rather have it diagnosed and tested in one visit — most companies will do it same-day for a flat service-call fee.
Call (888) 290-7421Frequently asked
Why is my garage door not closing if the sensors look fine?
Nine times out of ten it's alignment, dirt, or sun glare hitting the receiving eye, not a dead sensor. Wipe both lenses, make sure both LEDs glow steady, and check that nothing is blocking the beam near the floor. Loose wiring at the sensor or back at the opener is the next thing to check. If everything looks right and the door still reverses, then it's time to replace the sensors or have them tested.
Can I replace just one safety sensor, or do I need both?
You can technically replace just the failed one if you find a matching unit, but most homeowners and pros replace the pair. They're sold and priced as a set, they age at the same rate, and matching a single sensor to an old one can be a headache. Since the pair is usually only $15 to $50, doing both saves you a repeat trip up the ladder.
Is replacing garage door sensors a safe DIY job?
Yes — unlike springs or cables, sensors are genuinely DIY-friendly. They run on low-voltage wiring with no dangerous tension involved, so the worst-case mistake is the door not closing rather than an injury. The one non-negotiable step is the auto-reverse test afterward: the door must reverse instantly when the beam is broken. If it doesn't, don't use the door until it's fixed.
How much does a pro charge to replace garage door sensors?
Expect $85 to $200 total, which usually includes the service-call fee, the new sensors, alignment, and a full safety test. It's on the lower end for garage door repairs. If you're already paying for a tune-up or another fix, ask them to check the sensors while they're there — it's often bundled in at little or no extra cost.
Rather leave it to a pro?
Licensed local techs, same-day service, upfront pricing, and a 1-year warranty.