Door closes and jumps straight back up, one sensor light blinking, or the door refuses to close at all? The safety sensors are the first thing to check. We test the whole sensor loop, realign the beam, replace failed optics and prove the door completes a full cycle before we leave.
Sensor loop tested on every visit
Sensor faults look like door problems, which is why so many homeowners pay for the wrong repair. If any of these look familiar, the sensor loop is the place to start.
The opener runs but the door never moves on its own, so you end up pulling the handle by hand. That points at the safety circuit refusing to release the door, not at the motor.
A sensor knocked even a few millimetres off its mount stops seeing the other side. The bracket looks fine from standing height, but the beam is already missing.
A bracket fastened into crumbling concrete or a stripped screw works loose over time. Every small shift moves the beam, and the door starts failing on and off.
Eyeballing it is not enough. The two units have to sit level and square to each other, at the same height, with a clear line between them end to end.
Anything sitting in the line between the sensors — a bin, a curled hose, a parked bike — reads as an obstruction. Dust and cobwebs on the lens weaken the signal the same way.
This is what a sensor that ignores the floor leads to. The door drives into an obstacle, jumps the track and hangs crooked — a safety failure that turned into a structural one.
Four patterns cover nearly every sensor call we run in Arlington. Pick the one that matches what your door is doing.
The two units have to look straight at each other. When one bracket is nudged out of line, the receiver never sees the beam — and the opener treats the doorway as blocked.
Dust, cobwebs, pollen and condensation cut down how much of the beam actually reaches the receiver. The loop is closed on paper, intermittent in practice.
The thin low‑voltage wire runs from the opener head down to each sensor. A staple driven too tight, a splice that pulled apart, or corrosion in a garage that sees road salt will break the circuit at random.
A low sun can blind an infrared receiver the same way it blinds a camera. When the fault only happens at a certain hour, that is usually the cause — and when it happens on a brand‑new pair of sensors, the opener’s logic board is the next suspect.
A sensor fault is a safety problem, not an inconvenience. We treat it that way — diagnosing the whole circuit instead of nudging one bracket and hoping the door behaves.
The questions we get asked most on sensor calls in Arlington, VA.
That is the safety circuit telling the opener something is in the doorway. Most often one sensor is out of alignment, dusty, or the wire to it has an intermittent break. The door is not malfunctioning — it is doing exactly what it was designed to do when the beam is not confirmed.
They are the two small units mounted on the door track or the wall, a few inches above the floor, one on each side of the opening, facing each other. One sends the infrared beam and the other receives it.
No, and we will not do it. Since 1993 every automatic garage door opener sold in the US has been required to have a non-contact safety reversing system. Bypassing it removes the only protection for a child, a pet or a vehicle in the doorway. We fix the fault instead.
Watch the indicator lights. If one LED never lights at all, that unit has no power or has failed. If both light but the door still misbehaves, the alignment or the wiring between them is the likely culprit. The honest answer needs a meter on the circuit, which is what we do on site.
A blinking or flickering indicator almost always means the receiver is not getting a clean beam. Common causes are a knocked bracket, dust or cobwebs on the lens, or a loose wire connection. It can also mean the receiving unit itself has failed.
Low sun can flood an infrared receiver with light and blind it, the same way it blinds a camera lens. If the fault is tied to a time of day rather than an action, sun exposure at the sensor height is the first thing to check. Sun shields or repositioning usually solve it.
They can. Road salt and standing water corrode the terminals and the wire splices, and freezing temperatures can make a marginal connection fail outright. Northern Virginia winters are a common time for sensor calls for exactly this reason.
Only the failed unit usually needs replacing, but the pair is matched and the same age. We will tell you plainly whether replacing one is genuinely fine or whether a matched pair makes more sense for your door and opener.
Realignment and cleaning is typically a short visit. Wire or unit replacement takes longer because the circuit has to be re-tested. We serve Arlington, VA and the surrounding Northern Virginia area — call the shop, tell us your neighbourhood and we will confirm the next available slot.
