Why will a garage door opener open, but not close?

We get this question a lot too. We answer it on the phone when the person says they are confident with a little DIY. But, just be warned right here, right now, you need to be careful with adjusting the settings mentioned. They are specific safety features of your door that can cause these problems and you should follow manufacture guidelines when setting them!

Look at this discussion here: https://www.reddit.com/r/HomeImprovement/comments/2l82pz/liftmaster_wont_close_garage_door_but_it_will/

Do you see what everyone always answers? The first thing they blame is the safety eye sensors! Well, if that’s the case, it’s an easy garage door repair. Just line them back up. The big secret that no one wants to tell you, is they aren’t laser beams with pinpoint accuracy with no margin of error. They just need to be close. Here’s the easiest way to know if it is your sensors are causing you the headache. If when you click close, the door goes back up and the lights blink a few times, then it’s probably your sensors. There may also be an indicator light on the sensors when they are aligned that will let you know if they are out of sync. Here is how I recommend adjusting them.

How to adjust your sensors

Measure five inches up from the floor, and that’s where I always mount them. Safety recommendations say that they must not be mounted higher than six inches. Okay. You’ve got them mounted. Now, to align them. Eye ball it, and get it as straight over to the other side as possible. Now. There should be some indicator light when they are lined up. What I like to do, is see how far to one side I can point it before it turns off, point it the other way until it turns off. Then I align it right in the middle of those two. You’ll be surprised how large of a margin it allows! There’s nothing crazy about it. Grab some rubbing alcohol and clean the lenses on them so all the cob webs and dust are off of them while you’re down there.

My garage door sensors are fine! Now what??

This is the more likely scenario that I run into. A good test to do first, is disconnect the garage door opener and open and close the door by hand. Does it run smooth? Does it catch anywhere? Usually what the problem is in this case, is that the downward force is incorrect. Most people don’t even know such a thing exist, so let me explain. There is a downward force and an upward force. When closing and while properly adjusted, if the door hits something or cannot close under a specific amount of force the door will open back up. This prevents your door from being ripped apart if it gets stuck or if it runs into something that is not interfering with the sensors. It is a safety feature. Same thing for the upward force. If the door gets jammed, it will not tear it apart. It will simply stop.

Door out of track and falling
Incorrect downforce can pull a garage door out of its tracks and cause serious safety issues.

Doors get old. They wear. Rollers get sticky. Weather can make things run differently. (I get a lot of these calls as things turn to the nice cold winter of Ohio.) The fix is simple. Increase the down force. Not all the way at once. Increase the down force by 1 or 2 at a time until the door opens reliably. Then I increase it 1 more to give it a little margin. You should test the door with a 2×4 per manufactures specifications to make sure the safety requirements are met.


If any of that sounds out of your league, call us.  If you’re not close to us, call a reputable garage door repair company. There may be underlying causes like seizing rollers that need replaced or other common maintenance issues needing addressed. In fact, there could be problems with the internal components of the opener causing a need for the increase down force.

One last thing I’ll mention before wrapping this up, is something I’ve heard. Is that sun can cause problems with the sensors. I’ve never actually run into such an issue in the wild. If the sensors line up, they work. You can google it a little, and you can find what I mean about people saying the sun can cause issues with the garage door sensors. If the sensors are aligned and the downward force is not an issue, you can always try a piece of cardboard blocking the sun on the sensor and see if that fixes the issue.

GEM Garage Door Repair has probably missed out on a hundred service calls because we can usually help people with such issues over the phone. At the same time, I’m confident that those people have called us later or referred us to friends and family because we’ve helped them out. It’s our same belief  with providing an upfront, honest price. We feel we make more money by being honest and helpful than by making a quick buck on any job we get. We hope to earn your trust too! Even if it’s just a call and a referral later.