Garage door safety sensor repair and alignment in Ottawa

Door will not close and the light blinks? Here is why

A garage door that closes a few inches then reverses, while the opener light flashes, is almost always the photo-eye safety sensors. The two eyes near the floor are not seeing each other, so the opener stops the door to avoid crushing whatever it thinks is there.

This is the single most common reason a door will not close, and the good news is it is usually a five-minute fix. Before you call, look at the two small sensors mounted about six inches off the floor on each side of the door, and check that the green receiving light is steady. If it is dark or red, the beam is broken. Still blinking after a wipe and a nudge? Call us at (613) 255-1968 and we will realign it today.

Why won't my garage door close?

When the door reverses on its own, the cause is almost always a broken sensor beam: the eyes are out of alignment, the lens is blocked, a wire is loose, or the sensor has failed. Each one stops the door from closing until it is cleared.

The photo-eye sensors shoot an invisible infrared beam across the bottom of the opening. The opener will not let the door close unless that beam is unbroken. Here are the four faults we find, in order of how often they cause a no-close.

Sensors out of alignment, the most common cause

A bumped ladder, a stored bike, or a winter frost heave can knock a sensor a few degrees off, and that is enough to break the beam. The receiving eye turns red or goes dark. Loosen the wing nut on the bracket, point both eyes straight at each other until the green light holds steady, then tighten. If the brackets are bent or the wing nut is stripped, we replace them.

A blocked or dirty photo-eye lens

A spider web, a leaf, road salt film, or a leaning storage tote in front of the lens breaks the beam just like misalignment does. Wipe both lenses with a soft, dry cloth and clear anything within the beam path. In an Ottawa winter, snow and slush thrown off the car are a frequent culprit.

A damaged sensor wire or loose connection

The sensors run on low-voltage wiring back to the opener motor. A staple through the wire, a chewed cable, a corroded splice, or a terminal that has worked loose will kill the signal and make the light flicker. Repairing or rerunning that wiring is part of our garage door opener repair (sensors wire into the opener), since the eyes and the motor are one system.

Sun glare or a failed sensor

Low afternoon sun shining straight into the receiving eye can wash out the beam, so the door refuses to close at the same time each day. A sun shield or a small reposition fixes it. If a sensor stays dead after a clean wiring and alignment check, the eye itself has failed and we swap the pair.

What do the blinking sensor lights mean?

Each sensor has a small LED. A steady light means good, a flashing or dark light means the beam is broken. The opener motor also blinks its own light a set number of times to tell you exactly which fault it has detected.

Reading the lights tells you almost everything before a technician arrives. There are two sets of lights to check: the ones on the sensors, and the one on the opener motor itself.

Green versus red, or amber, sensor light

On a LiftMaster or Chamberlain unit, the sending eye glows a steady amber and the receiving eye glows steady green only when the two are aligned. If the green light is off, flickering, or red, the beam is broken. Genie and other brands use the same idea with their own colours, but the rule holds: steady is good, anything else means realign or clean.

How many times the opener light blinks

When the door will not close, watch the light on the opener motor. On many LiftMaster and Chamberlain models it blinks a code: a sensor fault often shows as a steady up-and-down flutter or a repeating burst. Counting the blinks narrows it to sensors, a logic board, or travel limits. Tell us the count when you call and we will arrive with the right part on the truck.

Can I just bypass the sensors?

No, and please do not. The photo-eye sensors are required by the UL 325 safety standard. They are the auto-reverse protection that stops the door on a child, a pet, or the back of a car. Bypassing them removes that safety, so we repair them instead.

Every opener built since 1993 must have working photo-eyes by law, and disabling them voids that protection and can void your insurance. Holding the wall button to force the door down is a temporary move only, never a fix. We realign or replace the sensors the same day so your door closes safely on its own again. Learn more about how this works in our guide to full-service garage door repair in Ottawa.

Why garage door sensors act up in Ottawa winters

Ottawa winters punish photo-eye sensors. Snow, ice, and road salt coat the lens, sub-zero cold makes low-voltage wiring brittle and connectors loose, and frost heave under the slab shifts the brackets out of alignment. A clean and a realignment usually clears the fault.

A door that closes fine in summer but reverses every January morning is the classic seasonal sensor complaint. Slush flung off the tires builds up around the lens, and the temperature swing between a heated car and a minus 25 garage fogs and ices the eyes. We wipe the lenses, reseat the wiring, square the brackets, and confirm a steady green light before we leave. While we are there we also check the door balance and rollers, since a sticky door strains the opener in the cold.

How much does garage door sensor repair cost in Ottawa?

Sensor realignment and rewiring fall under opener repair, from $150, with the service call free when we do the work. A full photo-eye sensor pair replacement runs about $150 to $250 installed, depending on your opener brand. There are no overtime fees, ever.

If all your sensors need is a clean and an alignment, that is often the only charge. If the wiring is damaged or an eye has died, we quote the part before we start, never after. The service call is $35 to $85 and free on any repair over $250. See our full breakdown of garage door repair costs in Ottawa so there are no surprises.