Garage Door Symptom Diagnoser — Why Won't My Door Open?
A garage door that won't move can be a $5 remote battery or a $450 dual-spring job — and a few of the causes are genuinely dangerous to touch. Answer a few questions to narrow down the likely cause, what it costs, and whether it's safe to fix yourself.
How this works
This diagnostic follows the same triage a garage door tech runs on the phone, built from Chamberlain/LiftMaster and Genie troubleshooting guidance plus industry diagnostic content: separate power and remote problems (cheap DIY fixes) from mechanical failures, then use the two tests that settle it — the manual-lift test and a visual check of the spring coil and side cables. A door that's suddenly too heavy to lift, or a 2-inch gap in the torsion spring, is a broken spring; a slack cable or crooked door means the cable is off its drum or the door is off track. The 10-flash check comes straight from the LiftMaster diagnostic table, where 10 flashes of the main light signals a safety-sensor obstruction or misalignment (sensors mount about 6 inches off the floor; some post-2022 boards dropped the 10-flash feature).
The DIY-versus-pro verdicts are safety calls, not upsells. Sensors, remote batteries, lock mode, GFCI resets, and a disengaged trolley are genuinely safe fixes anyone can do, and the steps here walk you through them. Springs and cables are different: both hold the door's full weight under wound tension, and every pro outcome in this tool says the same thing — do not operate the door, and don't touch the tension system. Cost ranges come from 2026 national pricing (Angi, HomeGuide): $200–$300 for a single torsion spring installed and $250–$450 for a pair, $150–$250 for cables, $150–$400 for opener repairs, and $250–$550 for a new opener installed.
It's a screening tool, not an inspection — a tech confirms the diagnosis on site. Garage Door Repair Network is a referral service: we route requests to independent local techs, and the urgent results here are exactly the calls they prioritize.
Estimates only — independent local providers quote their own pricing. Data last reviewed 2026-07.
Frequently Asked Questions
How do I know if my garage door spring is broken?
Three reliable signs: you heard a loud bang from the garage; the door is suddenly far too heavy to lift by hand; and there's a visible gap of about 2 inches in the spring coil above the door. Any of those means stop using the door and call a tech — springs are under extreme tension and are not a DIY repair.
Why does my garage door start to close, then go back up?
That's the safety-sensor system doing its job — or misfiring. If the photo eyes near the floor are blocked, dirty, misaligned, or hit by direct sunlight, the opener assumes something is in the way and reverses. On most LiftMaster/Chamberlain units the main light flashes 10 times when this happens. Cleaning and realigning the sensors fixes it in most cases, for free.
Is it safe to open my garage door manually when the opener is dead?
Yes, if the springs are intact: with the door fully closed, pull the red release cord and lift. The door should feel light and stay put halfway up. If it's extremely heavy or slams down, the spring is broken — stop immediately and leave the door alone until a tech arrives. Never pull the release cord while the door is open.
What does it cost to fix a garage door that won't open?
It depends entirely on the cause: a remote battery or GFCI reset is free-to-cheap, sensor realignment is usually free, a single torsion spring runs $200–$300 installed ($250–$450 for a pair), cables $150–$250, and opener repairs $150–$400 with new openers at $250–$550 installed. That's why diagnosis comes first.
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Use the free tool →Prefer to just talk to someone?
Call or send the short form — we'll route you to an independent local pro.