Garage door sensors not working?Fix them in this order

Work through it in this order: clear the path, wipe both lenses, line the eyes up, shade the receiving eye from the sun, then trace the wire back to the opener. Each step is below, with the two tests that prove the fix.

The two photo eyes near the floor hold an infrared beam across the opening. On openers built to the U.S. standard, a closing door that meets a broken beam reverses to fully open and stops [16 CFR 1211].

Test the door before you trust it again. If it has to be shut tonight, skip to closing it with faulty sensors.

Because the photo eye has lost its beam, or the opener has found a fault in the eye's circuit; on openers built to the U.S. standard, either one sends a closing door back up [16 CFR 1211]. Where it turns back sorts it out:

• Part way down, touching nothing, it returns to the top: usually the beam. If both sensor lights stay steady while it happens, the beam is holding; look at the door instead. A door that binds or sticks, or will not stay put part way open, should be serviced [U.S. CPSC].
• It will not close at all, or turns back almost at once: possibly a fault in the eye or its wire, as the wire section explains.
• It reaches the floor or something on it, then goes back up: the opener's contact reversal in the table below. The eyes play no part; look to the opener's adjustment or a door that is heavy or binds.

Read any blinking light on the opener or a sensor against the opener's manual. On Chamberlain's sensors both lights should glow steady once nothing blocks the beam, and its line-up steps below deal with a green light that keeps blinking [Chamberlain].

The U.S. standard keeps the two reversals separate [16 CFR 1211]:

A recycling bin or a bike parked a little too far in will break the beam, and the eye sends the closing door back up, as the U.S. standard asks of it [16 CFR 1211]. Clear anything out of the beam and try the door again.

Then wipe both lenses with a soft, dry cloth before you touch the brackets, so you never realign an eye that only needed cleaning.

Point the two eyes straight at each other: Genie says its sensors must stay aligned to hold the infrared beam [Genie].

One eye sends the beam and the other receives it. Chamberlain marks its sending eye with an amber light and its receiving eye with a green one [Chamberlain]; Genie uses red and green [Genie]. Other makes may use other colours, so check your manual.

To realign Chamberlain's sensors:

1. 01Clear anything blocking either eye. Both lights should then glow steady [Chamberlain].
2. 02If the green receiving light blinks, loosen its wing nut, turn the eye until the light is solid, and tighten the nut [Chamberlain].
3. 03If it still blinks, do the same with the amber sending eye [Chamberlain].

Yes. Chamberlain says sunlight shining into its receiving eye can block the infrared light from the sending eye [Chamberlain]. The clue is timing: the door refuses only at the time of day when the sun reaches that eye, and closes normally the rest of the day.

Genie's fix for its sensors is to keep the green receiving eye out of direct sun. The eyes may move farther from the door opening, but not farther off the wall and not more than 6 inches off the floor [Genie].

In a garage with two doors, the signals can also cross between the pairs. Genie's answer is to mount the two sending eyes back to back, or the two receiving eyes back to back [Genie].

If the door still will not close once the eyes are lined up, Chamberlain's next step is to check the wiring connections [Chamberlain].

A wiring fault can look like a stuck door. The U.S. standard counts an open or short circuit in the wire between the eye, the opener and its power supply as a fault, and one response it allows is to keep an open door from coming down more than 1 foot (305 mm) [16 CFR 1211].

Follow the thin wire from each eye back to the opener and look for a cut, a pinch, a loose end or chewed insulation. Unplugging the opener to reset it will not mend any of those; the fault stays until the wire is put right.

Run one test for each column of the table above.

1. 01The beam: as the door closes, break the beam with an object held low, never a foot or a hand. It should reverse to fully open and stop [16 CFR 1211].
2. 02Contact: close the door onto a 2 by 4 laid flat in its path, or any 1 1/2 inch object. It must reverse on contact; the U.S. standard has opener manuals say so, and say to test monthly [16 CFR 1211].

Keep everyone, pets included, out of the doorway while you test.

Press the wall control and hold it until the door is all the way down. Chamberlain documents this for its openers while the sensors are at fault, but says openers and replacement logic boards it made after February 3, 2022 no longer have it [Chamberlain]. On any other make, it is worth one try.

If that does nothing, the emergency release is the only other way down, and with the door up it takes two people: one holds the door's weight while the other pulls the release. On your own, leave the door open and keep everyone out from under it.

Lower it slowly and stop about halfway. In U.S. CPSC guidance, a balanced door stays put when stopped part way open; one that is not balanced, or that binds or sticks, should be serviced by a professional, and a severely unbalanced one can crash to the floor [U.S. CPSC]. Keep hold until it is down.

No, and not because of the '1993 federal law' other pages cite. That sensor requirement is the U.S. CPSC standard, 16 CFR Part 1211, for residential openers made on or after January 1, 1993 for sale in the United States [16 CFR 1211], not an Ontario or Canadian law.

The reason is in the table above: without the eyes, all that protects someone under a closing door is the contact reversal, which starts only once the door has hit them [16 CFR 1211]. Never bypass the sensors to get the door down.

The Ontario rule we can point to is about approval: O. Reg. 438/07 bars using or selling an electrical product or device governed by the Ontario Electrical Safety Code unless it is approved, and one route to deemed approval needs, among other things, a certification body's report and its mark for use in Canada [O. Reg. 438/07].

Call a technician when:

• the door fails the 2 by 4 test, and the opener has to stay disengaged until it is put right [U.S. CPSC]
• it reaches the floor and goes back up, which points to the opener's adjustment or the door, not the eyes
• it will not stay put part way open, or it binds or sticks [U.S. CPSC]
• the lights will not hold steady after you have cleaned the lenses, lined up the eyes and checked the wire, which leaves the sensor pair itself to replace
• the damaged wire runs where you cannot reach it safely

If it comes to a new opener, look for a certification body's mark for use in Canada, part of the Ontario approval route above [O. Reg. 438/07].

If the door is still standing open tonight after all of this, call: Modern Empire Doors is open 24/7 including weekends and holidays. Say where the door turned back and which test it failed.