1
Look at the two LEDs
One sensor shows a steady green (sending) light, the other a steady amber or red (receiving) light. A blinking or dark receiving LED means the pair is not aligned or not powered.
Safety systems
Garage Door Sensor Repair in Denver
Door reverses on its own, blinks and won't close, or only misbehaves in the afternoon sun? Start with the five checks below — or have a technician out today.
Quick answer
A garage door that reverses before closing almost always has misaligned or dirty photo eyes. Cleaning and re-aiming the sensors costs $89–$129 in Denver; a full sensor pair replacement runs $145–$215 including the service call.
- Typical cost
- $89–$215
- Response time
- Same day · 30–60 min on site
- Guarantee
- 1-year parts & labor
Call (720) 207-7666
Content reviewed and priced for by our Denver service team.
Fix the sensors in 5 checks
2
Wipe both lenses
Denver dust, cobwebs and road salt film block the beam. Clean each lens with a dry microfiber cloth — never a wet spray, which seeps into the housing.
3
Re-aim the brackets
Loosen the wing nut, tilt the misaligned sensor until the LED stops blinking, then tighten. Both eyes must sit at the same height, no more than 6 inches above the floor.
4
Check the wire runs
Staples through insulation, rodent chew marks and brittle 30-year-old bell wire are the most common Denver failures. A nicked conductor reads as a permanently blocked beam.
5
Test the reverse
Place a 2x4 flat under the door and close it. The door must reverse on contact. If it does not, the safety system still needs service — do not leave it bypassed.
What the blink codes usually mean
- Receiving LED blinking: beam blocked or eyes misaligned
- Receiving LED dark: broken wire or dead sensor
- Both LEDs dark: no power to the sensor circuit
- Opener light flashes 10 times: LiftMaster sensor fault
- Door closes only with the wall button held: sensors disabled
- Works at night, fails at 5pm: direct sunlight on the eye
Sensor repair FAQ
How much does garage door sensor repair cost in Denver?
Alignment and cleaning on a service call runs $89–$129. Replacing a failed safety sensor pair including the visit is $145–$215, and repairing chewed or broken sensor wiring is $120–$190 depending on the run length.
Why does my garage door close a foot then go back up?
That is the classic blocked-beam signal. The opener starts the close cycle, loses the sensor signal partway and reverses. Ninety percent of the time it is a bumped bracket, a dirty lens, or direct low-angle Colorado sun washing out the receiving eye.
Can I bypass the safety sensors?
No. Federal law has required photo eyes on residential openers since 1993, and bypassing them is how children and pets get crushed. If you need the door shut right now, hold the wall button down continuously — that is the legal constant-pressure override.
Do sensors need to match the opener brand?
Yes, in practice. LiftMaster, Chamberlain, Genie and Overhead Door all use different voltages and connector logic. We stock OEM pairs for the brands common in Denver so the fix is done on the first visit.
Why do my sensors only fail in the afternoon?
Direct sunlight hitting the receiving eye overwhelms the infrared beam. West-facing Denver garages see this from about 4pm onward. A short sun shield or repositioning the sensor solves it permanently.
Door still refusing to close?
We test the full safety system, not just the eyes, on every visit.
Call (720) 207-7666