The Short Version
If a garage door starts closing and then reverses, nine times out of ten the safety sensors are the problem. The exceptions are worth knowing before you spend an afternoon fiddling with sensor brackets: a door that won't move at all, makes no sound, or hums without closing is usually an opener or power issue, not a sensor issue. And a door that reverses at the exact same spot every single time, rather than randomly, often points to a track obstruction or a worn roller rather than the electronic eyes.
What the Symptoms Are Telling You
Before you call anyone, it helps to pin down which of these you're actually seeing, because each one narrows down the cause:
- Closes a few inches, then shoots back up — almost always the sensors or something blocking their beam.
- Closes most of the way, then reverses near the floor — often a limit setting problem, or a track that's slightly bent near the bottom.
- Won't close at all, opener is silent — check power first: tripped breaker, unplugged unit, or a dead wall switch.
- Opener hums but the door doesn't move — points toward the motor, drive gear, or a broken spring taking on too much of the door's weight.
- Closes fine some days, not others — classic sign of sun glare or dust interfering with the sensors, which is common here during the dry, smoky stretches of fall.
The Order a Technician Checks These Issues
1. Safety Sensors (Photo Eyes)
These are the two small boxes mounted a few inches off the floor on either side of the track, and they're the first thing any technician looks at because they cause the majority of reversing complaints. The sensors have to see each other in a clean, unbroken line. Dust from a dry summer and lingering wildfire smoke haze can leave a fine film on the lenses that's barely visible to the eye but enough to block the signal. Spiderwebs, a stray garden hose, or a bike leaned against the track can do the same thing. Low fall sun hitting the sensor lens directly can also wash out the beam at certain times of day. The fix is usually simple: wipe both lenses with a soft cloth, make sure both brackets are tight and aimed directly at each other, and check that nothing sits in the beam's path. If one sensor's light is dim or flickering, the wiring or the sensor itself may need replacing.
2. Opener Limit and Force Settings
Every garage door opener has a limit setting that tells it how far to travel before it should be fully closed, and a force setting that tells it how much resistance to push through before assuming something's in the way. If these are off — which can happen after a power surge, a battery backup reset, or just age — the opener may think the door has hit an obstruction when it's actually just reached the floor. A technician checks these settings against the actual door travel and adjusts them incrementally, testing each time, rather than cranking them up until the symptom goes away.
3. Track Alignment and Obstructions
Next comes a physical inspection of the tracks themselves. Homes on uneven foothill lots, slab shifting from seasonal ground movement, or framing adjustments from earthquake retrofit work can all nudge a track slightly out of alignment over time. A track that's even a quarter-inch off can cause the rollers to bind at a specific point, which the opener reads as resistance and reverses to avoid. Dirt and gravel kicked up during dry months can also build up in the track and cause the same effect. The fix ranges from a simple cleaning and lubrication to loosening and re-securing the track brackets, or replacing a track section that's visibly bent.
4. Spring Tension and Door Balance
If the door is heavy to lift by hand when disconnected from the opener, the springs are likely worn or losing tension — and an opener straining against an unbalanced door will often stall or reverse rather than force it. This is checked by disconnecting the opener and manually testing how the door moves and holds position partway up. Spring replacement is not a do-it-yourself repair; the springs are under high tension and a technician will match the new springs to the door's weight and cycle rating before reinstalling.
5. Opener Logic Board or Motor
If sensors, settings, and tracks all check out, the last stop is the opener itself. A failing logic board, worn drive gear, or motor on its way out can cause inconsistent behavior that mimics a sensor problem. This is usually diagnosed by process of elimination and often means opener repair or, if the unit is older, a straightforward opener replacement.
When to Call Sonora Garage Door Service
If you've wiped the sensors, cleared the track, and the door still won't close reliably, it's time to call in a technician rather than keep guessing. We'll run through opener diagnostics, check spring balance, and inspect the tracks in person, then walk you through exactly what's causing it before we touch anything. Most visits end with either a sensor or opener repair, or, if the springs are the culprit, a same-visit spring replacement.
If your garage door in Sonora, Twain Harte, Columbia, or anywhere in Tuolumne County is reversing, sticking, or refusing to close, give Sonora Garage Door Service a call — we'll get it diagnosed and fixed right the first time.