QUICK ANSWER
A garage door that opens fine but won’t close all the way — or closes partway and reverses back up — is almost always caused by the safety sensors, an obstruction in the track, or a misadjusted close-limit setting. It’s one of the most common calls we get, and the fix is often something you can check yourself in a couple of minutes. Here’s where to look, in order, and when to call (801) 814-1053.
1. The Safety Sensors (the most common cause)
If the door reverses before it touches the ground, dirty or misaligned safety sensors are the most likely reason. Every modern opener has two small sensors mounted near the floor, one on each side of the door track. They shine an invisible beam between them, and the opener refuses to close if that beam is broken — it’s a safety feature to stop the door from closing on a person, pet, or object. Wipe both lenses clean with a dry cloth, remove anything sitting in front of them (even a stray leaf or spiderweb can trip it), and check that the small indicator light on each sensor glows solid, not blinking. If one is blinking, loosen its mounting screw and gently nudge it until both lights go solid, then re-tighten.
2. Something in the Track
A stone, chunk of hardened grease, or a bent section of track anywhere along the door’s path will stop it short. Run your eyes up both tracks from the floor to the top of the opening. Anything the rollers strike on the way down will make the opener think it’s hit an obstacle and reverse the door as a safety response. Clear any debris you find; if the track itself looks bent or pinched, that’s a job for us rather than something to bend back yourself.
3. The Close-Limit Setting
If the sensors are clean and the track is clear but the door still stops a few inches short every time, the opener’s close-limit setting is probably off. This setting tells the opener exactly how far down “closed” is. If it’s set too conservatively, the opener stops the door early or reverses it thinking it hit resistance. Most openers have small adjustment dials or buttons for this, but the correct setting is specific to your exact door and track — get it wrong and the door either stops short or slams too hard. This is one we’re usually happy to just dial in for you on a maintenance visit.
4. Worn Rollers, a Frayed Cable, or a Tired Spring
If the door hangs unevenly, feels unusually heavy, or grinds as it moves, worn hardware — not the sensors — is the real problem. A frayed cable lets one side of the door drop lower than the other, which the opener can read as an obstruction. A weakening spring makes the whole door heavier for the opener to control, and it may struggle to finish the close cycle at all. Neither of these is a DIY fix — a cable or spring under tension can cause serious injury if it lets go while you’re working on it. See our off-track & cable repair and spring repair pages for what those repairs involve.
How to Test the Sensors Yourself
Wave a broom handle or a piece of cardboard through the beam between the two sensors while the door is closing — if it stops and reverses, the sensors are working; if it keeps closing anyway, they’ve failed and need replacing or realigning. Most sensor units have a small LED: a steady light on both sides means they’re aligned and seeing each other, while a blinking or dark light points to either misalignment or a bad connection. If wiping the lenses and re-aiming them doesn’t get a steady light, the sensor itself (or the wire running to it, which mice and yard work can damage) may need replacing — a quick, inexpensive fix compared to most other opener repairs.
Quick Diagnostic Checklist
- Door stops at the exact same spot every time, no reversal light blinking? Likely the close-limit setting.
- Sensor light blinking, or door reverses immediately after touching down? Check the sensors first.
- Door hangs crooked or one side seems to move differently than the other? Cable or spring issue — call us, don’t force it.
- Grinding or scraping noise as it moves? Worn rollers or track debris.
Frequently Asked Questions
Why does my door open fine but won’t close?
Opening doesn’t rely on the safety sensors, but closing does — that’s why a sensor problem shows up specifically when you try to close, never when you open.
Is it safe to keep using a door that reverses randomly?
Yes in the short term — that’s the safety feature working as designed. But treat it as a sign something needs attention rather than ignoring it, since the underlying cause (worn cable, failing sensor) tends to get worse over time.
How much does it cost to fix a door that won’t close?
If it’s a sensor alignment issue, that’s often included in a standard service call. If it’s a cable or spring, expect the same range as our spring replacement cost guide.