# Garage door won't close and the sensors are blinking? Three ways forward > A door that reverses or will not close, with a blinking light, can mean a realignment, a new pair of sensors or an old opener. What each gets you, what to ask on the quote, and when the cheapest is the right call. Source: https://garagedoorscience.com/blog/garage-door-sensors-blinking-three-options · by sara · published 2026-10-24 · updated 2026-10-24 You press the button and the door starts down, stops and goes back up. Or it will not close at all, and a light on the opener or on one of the two small sensors by the floor is blinking. There are three real ways forward, and they cost very different amounts. This page is about the decision and the quote. It does not repeat the troubleshooting steps. Those are on [our photo-eye page](/blog/garage-door-photo-eye-troubleshooting), [our page on what the opener light is telling you](/blog/garage-door-opener-light-blinking-patterns) and [our page on how the sensors work](/blog/garage-door-safety-sensors). Start there, because the first option is yours to try. ## Never turn the sensors off The sensors are the part that stops a closing door when something is in the way. Chamberlain's [owner's manual for its B980 opener](https://cgi.widen.net/content/vlzppckqt9/original/114a5126.pdf) says: "This required safety device MUST NOT be disabled." A door that will not close is a reason to fix the sensors. It is never a reason to switch them off or work around them. ## Option 1, the good: clear it, realign it, check the wire The two sensors face each other across the opening, one on each side near the floor. The same manual says the sending sensor has an amber light and the receiving sensor has a green one, and that the lenses should point toward each other. **What it gets you:** often the whole fix, for nothing. [Chamberlain says](https://support.chamberlaingroup.com/s/article/How-To-Troubleshoot-The-Safety-Reversing-Sensors-When-One-LED-Is-Off-Or-Flickering) the sensors must be connected and aligned correctly before the opener will move the door down, and that once any obstruction is cleared the lights in both sensors should glow steady. Chamberlain's owner's manual adds that you should make sure the sensor wire is not shorted or broken. Our [photo-eye page](/blog/garage-door-photo-eye-troubleshooting) has the steps. **If you call someone:** [HomeAdvisor lists sensor realignments at $150 to $250](https://www.homeadvisor.com/cost/garages/repair-a-garage-door/) (updated Jun 20, 2026). **What to ask:** whether the technician checked the wire as well as the alignment, and whether they tested that the door reverses when something is in its path before they left. ## Option 2, the better: replace the pair Both sensors are replaced with a new pair. **What it gets you:** two new sensors in place of two that will not glow steady after you have cleared the path, realigned them and checked the wire. That reasoning is ours. Chamberlain says the lights glow steady when the sensors are aligned and wired correctly, so a pair that cannot do that after those checks is the one to question. **What it costs:** we have no sourced price for a replacement pair. Ask for the part price and the installed price as two numbers, so you can compare two quotes. **What to ask:** why the technician thinks it is the sensors and not the wire, the alignment or the opener. Ask whether the new pair is made to work with your opener, and whether they tested the door's reversal afterward. We have no manufacturer's guidance to quote on matching sensors to openers, so that answer has to come from the technician in writing. ## Option 3, the best: replace the opener The opener is replaced, and the sensors are part of the question. **What it gets you:** a new opener with a new warranty, which you should ask to see in writing. [HomeAdvisor puts](https://www.homeadvisor.com/cost/garages/install-a-garage-door-opener) installing an opener at $218 to $540, with an average of $379 (updated Jun 20, 2026). **How old is too old:** the [NAHB and Bank of America *Study of Life Expectancy of Home Components* (2007)](https://sghac.com/site/wp-content/uploads/NAHB-Lifetimes.pdf), which we read on October 14, 2026, lists garage door openers at 10 to 15 years. It is a typical range from an old source, not a promise about your unit. [Our opener lifespan page](/blog/garage-door-opener-lifespan) says more, and [our page on an opener that quit](/blog/garage-door-opener-not-working-three-options) walks through that choice. **What to ask:** whether the quote includes new safety sensors or reuses yours, and whether removal of the old opener is in the price. ## When the cheapest option is the right call Option 1 is usually the right place to start, and it is not a sign of a bad technician. This part is our judgment, not a manufacturer's or an industry standard. It fits when: - **It started after something changed.** A bumped sensor, a box pushed against one, a spider web across a lens, or sun on the receiving sensor at the same time each day. - **One light is off or blinking and the other is steady.** That points at one sensor, not at the opener. - **A realignment brings both lights to steady and the door closes.** Then you are done. It does not fit when the same fault comes back after a clean realignment and a wire check. Then the sensors, the wire or the opener is the question, and a second visit for the same fix is the expensive way to find that out. It also does not fit when the opener is 10 years old or more, the low end of the NAHB range, and the repair is a large part of what a new one costs. ## What to put on any sensor quote 1. What was found, in writing: alignment, wire, the sensors or the opener. 2. The part price and the labor as two numbers, or one installed price. 3. A test of the safety reversal before the technician leaves. 4. Whether new sensors come with a new opener. Two quotes with the same four lines are easy to compare. ## What not to do Do not disable or bypass the sensors, and do not touch the springs, cables or bottom bracket on the door. Those parts are under tension and belong to a trained technician. If the door feels very heavy, drops fast or will not stay up, do not lift it, and call a professional. ## What to do today 1. Look at the two small sensors by the floor and note whether each light is steady, blinking or off. 2. Clear anything from the path and follow the steps on [our photo-eye page](/blog/garage-door-photo-eye-troubleshooting). 3. If that does not fix it, get a written quote with the four lines above, and choose the option that fits the age of your opener.