WiremanWireman · Garage door opener won’t close: troubleshooting for electricians · 2023 NEC ·
Garage door opener won’t close
Safety sensor alignment and wiring, then power and the opener’s force and limits.
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How it works
A residential garage door opener won’t close unless its safety reversing sensors (photo eyes) see each other across the door opening. UL 325 has required them on residential openers since the early 1990s, mounted no more than 6 inches above the floor. One sensor sends an invisible beam and the other receives it; each has an indicator light. The sensors connect back to the opener with thin low-voltage wire that’s easy to damage.
Every question and answer in this guide. Tap “Step by step” to walk through it.
- What happens when you press close?
- Won’t move, or reverses, and the light flashesLook at the indicator lights on both sensors. What do you see?
- One is off or flickeringClean both lenses and line them up: loosen the bracket, aim them at each other, and tighten. Is the light steady now?
- Yes, steady nowSensors were misaligned or dirty
- Still off or flickeringTest: Check the sensor wiringExpect: Continuity with the far end twisted, and open with it untwisted.
- Shorted, open or damagedDamaged sensor wire
- Wire tests goodFailed safety sensor
- Both are offTest: Check the sensor wiringExpect: Continuity with the far end twisted, and open with it untwisted.
- Shorted, open or damagedDamaged sensor wire
- Wire tests goodFailed safety sensor
- Both steadyWall control or opener logic
- One is off or flickeringClean both lenses and line them up: loosen the bracket, aim them at each other, and tighten. Is the light steady now?
- Closes only while holding the wall buttonLook at the indicator lights on both sensors. What do you see?
- One is off or flickeringClean both lenses and line them up: loosen the bracket, aim them at each other, and tighten. Is the light steady now?
- Yes, steady nowSensors were misaligned or dirty
- Still off or flickeringTest: Check the sensor wiringExpect: Continuity with the far end twisted, and open with it untwisted.
- Shorted, open or damagedDamaged sensor wire
- Wire tests goodFailed safety sensor
- Both are offTest: Check the sensor wiringExpect: Continuity with the far end twisted, and open with it untwisted.
- Shorted, open or damagedDamaged sensor wire
- Wire tests goodFailed safety sensor
- Both steadyWall control or opener logic
- One is off or flickeringClean both lenses and line them up: loosen the bracket, aim them at each other, and tighten. Is the light steady now?
- Starts down, reverses, no flashingForce or travel limit, or a binding door
- Nothing at all, no lights or soundIs the opener plugged in, and does that ceiling receptacle have power?
- GFCI or breaker tripped, or outlet deadNo power to the opener
- Outlet live, opener deadOpener has failed
- Won’t move, or reverses, and the light flashesLook at the indicator lights on both sensors. What do you see?