Short answer: check the safety sensors first
If your garage door starts closing and then reverses back up, or refuses to close at all, the single most common cause is a pair of small sensors near the bottom of the tracks called photo eyes. They're a safety feature, and when anything interrupts the beam between them, the opener assumes something is in the way and reverses the door. Before assuming a bigger mechanical problem, this is where a technician starts and where most homeowners can check things themselves.
What the symptoms actually look like
A door that reverses usually gets partway down, sometimes just a few inches, sometimes almost all the way, before it stops and goes back up on its own. A door that won't close at all often just sits there when you press the button, or closes for a second and immediately reopens. Both point to the opener's safety or travel logic rejecting the close command, rather than the motor itself failing.
The checks, in the order a technician runs them
1. Photo-eye sensor alignment and cleanliness
The two sensors sit a few inches off the floor on either side of the door opening. They need to face each other exactly and stay free of dust. During Chatsworth's dry stretches, blown dust and wildfire-season haze settle on the lenses fast, and that film alone can break the beam intermittently. Low fall sun angles can also cause glare directly into one sensor in the morning or evening. The fix is simple: wipe both lenses, confirm the indicator lights on each unit are solid rather than flickering, and nudge the brackets until the lights stay steady with nothing in the doorway.
2. Something physically blocking the beam path
Leaves, a stored bike, a trash can, or even a cobweb across the sensor line can trigger a reversal. This gets checked right after sensor alignment because it mimics the same symptom but needs no tools, just clearing the path.
3. Debris or resistance inside the tracks
Dirt, dried leaves, or grit built up in the track channel can create enough resistance that the opener reads it as an obstruction and reverses. This is more common after a long dry season when dust has had time to accumulate, right before the first winter rains wash it around and pack it into corners. Cleaning the tracks with a stiff brush and checking for anything wedged in the roller path usually resolves it.
4. Limit switch or close-travel settings
Every opener has a setting that tells it how far down to travel before it considers the door fully closed. If this limit is set to stop too early, the opener can misread the door as hitting an obstruction and reverse it. If it's set too far, the door may try to keep pushing down into the floor and bounce back. Adjusting this is a quick fix on most modern openers through a learn button or dial, but it requires knowing the correct travel distance for that specific door.
5. Bent or misaligned tracks
If the door only reverses at the same spot every time, a bent track or a bracket that's shifted is often the cause rather than the sensors. Houses that have gone through earthquake retrofitting sometimes have garage door framing that's slightly out of its original alignment, which puts uneven pressure on the tracks over time. This needs a hands-on inspection and usually a track adjustment or replacement section.
6. Spring tension and door balance
A door that won't close at all, rather than reversing partway, can mean the springs have weakened to the point the opener can't manage the door's weight safely, so its internal force sensor cuts the command. This is checked toward the end because springs are under high tension and testing them safely takes the right tools.
When to call Chatsworth Garage Door
If cleaning the sensors and clearing the tracks doesn't solve it, or if the door is heavy to lift by hand and clearly out of balance, it's time to call in a technician rather than keep adjusting settings. Chatsworth Garage Door handles both diagnostic Garage Door Repair calls and Spring Replacement when worn springs are behind the problem, and we check every step above in the same order before replacing any part.
If your garage door in Chatsworth, CA is reversing or won't close, call Chatsworth Garage Door for a same-week diagnostic visit.