I knocked the sensors out of alignment on my garage door. It will no longer operate. How do I fix it?

My garage door has sensors at either side near the bottom. I accidently hit one and now my garage door won’t operate. I tried to adjust it and I still cant get it to work. I don’t want to call a repair man because I know that there must be an easy and inexpensive way to fix it. Please help!

3 Responses to “I knocked the sensors out of alignment on my garage door. It will no longer operate. How do I fix it?”

  1. ealexbryan says:

    Get a ruler or a very accurate leveling equipment and adjust both sides of the optic eye in the sensors that they focus directly at each other. Both infrared lights should be interlocking , of course you will not be able to see it with the naked eye but once they interlock that should pretty much do it.

  2. ever1wolf says:

    I just recently installed a new door opener and security system.

    You don’t mention if you damaged or moved the track, or if the sensors light beams are aligned. The alignment should be relatively simple. Remember it’s similarity to any LASER you may have seen in a Movie. The Beam depends on the tolerance level, variable scope of each light source connecting with the opposite one.

    If the sensors lights do function and one is red and the other green,,,for example, that should determine the functionality of the units. If the track the door rides on has been twisted, moved, in any way then it isn’t the sensors.

    Also check the connections at the point on each sensor, they too may have been corrupted in the effect of "KNOCKED"

    Rev. Steven

    In the meantime your garage door mechanism should have a release lever,,,Use it for now.

  3. Dan says:

    Most auto garage door sensors built in the last several years have an indicator LED on them, usually green, that light up when the sensors are aligned. Lacking that, your stuck with some sort of aligning process like the first answerer indicated. Before you get to carried away, consider that you might have broken the sensor and aligning it would be fruitless. You may have distorted the mounting brackets or other peices of the garage door frame to the point that it is blocking the sensor. Check that also. Finally, I’m attaching a bunch of information I’ve collected from various sites about garage door openers. I had a similar problem a few months ago. After considering buying all new things, it turned out to be broken wires at the sensor. Rather long, there is a lot of information that may or may not be of use to you but it is all worth reading through and might give you some ideas.

    Check for broken, frayed and/or chewed wires at sensor(s). Wires are typically 16-18 gauge and are easily broken. Check for continuity through sensor by hooking both sensor leads to volt/ohm meter. Good sensor will show direct "short". There is no apparent voltage at lead-in wires. Solder all connections. LED on sensor will light when properly wired and aligned (this indicates some voltage present at lead-in wires but must be minimal).

    My garage door will not go down using my transmitters. I can only get the door down by holding down on the wall button.

    When the infra-red sensors are malfunctioning, usually one of the sensor lights will be blinking. The problem is either due to a blocked path beween the sensors, dirty eyes, loose wires at the sensors or at the motor head, or just bad sensors. You will find that the door will only move an inch or so in the close direction. When this happens your garage door will only close by using the wall button or wall console to override the safety and close the door by holding down on the button until the door fully closes. The transmitters (remotes) will not work to close the garage door.

    To try and correct the problem, make sure the eyes on the sensors are clean, the wire connections are securely fastened at the sensors and motor head, and the eyes are directed at each other. Also, try unplugging the garage door opener and re-plugging the unit back into the outlet. This acts as a reset and may reset the sensors. If nothing works, it may be that you have to replace the sensors. You can find new sensors on our Web site in the Genie section.

    Opener tries to operate, but the door does not move

    • A door spring may have broken. Visually inspect the door hardware for any broken springs. Have a qualified garage door service professional repair the door if any door hardware is broken.
    • In cold weather climates, check that the door is not frozen to the ground or that snow buildup is not blocking the door.
    • If the opener’s light flashes four times, the door force setting may be set too low

    How do I make force adjustments?

    The force adjustments control the pressure used to open and close the door. A new garage door opener from the factory is set to the lowest possible force adjustment. If you have a properly-balanced door, the forces required to open and close the door should be minimal.

    The force adjustments are usually located on the rear of the garage door opener and/or under one of the light lenses, if your opener has two lights. If you have lights on the side of your opener, the force adjustment will be located under the right light lens. The force adjustments are labeled with an arrow indicating open or close and numbered 1 to 9, with one being the lowest force and nine the highest. The force adjustments can only turn 260 degrees, or ¾ of a complete turn. Changes to the forces should be done in 10-degree increments. Please remember that too much force will interfere with the proper operation of the safety reversal system. Do not increase the force beyond the minimum amount required to close the door. Do not use the force adjustments to compensate for a sticking, binding, or unbalanced garage door.

    After adjusting the opener, always test the safety reverse system. We recommend repeating this test monthly.

    Place a one inch board (or 2 x 4 laid flat) on the floor, centered under the garage door. Operate the door in the down direction. The door must reverse upon striking the board. If it does not, refer to your owner´s manual, call your local LiftMaster Authorized Dealer or speak to one of our technical service representatives by calling our S.O.S. HotLine® at 1-800-528-5880. Failure to pass the above test could result in serious injury or death.

    My GDO starts to close then goes backs up.

    Check the safety sensors. 9 times out of 10 the sensors have been bumped, have something in front of them, or are just plain dirty. All these situations will cause the sensors to tell the GDO not to close there could be an obstruction. There are indicator lights on the sensors which should be glowing steady. Re-adjust the sensors and you should be back in business.

    2. My door won’t close or goes a few inches stops and comes back up.

    Most openers have infra-red sensors that mount on either side of the garage door a few inches off the floor.
    Check that they can "see" one another. The IR receive sensor led should turn on and off as you break the beam with your hand. Verify led on IR receiver is fully on and not faintly flickering. You may need to cup your hand over led to verify this status as flickering levels are easily overlooked (light level should be steady). You want IR sensors perfectly aligned If the alignment is “marginal” the vibrations encountered during operation will trigger a momentary break and your door will go back up. The door won’t close if beam is broken. Align the sender first by eye and then the receiver using the led indicator as your guide. Make sure the wires that go to the back of the sensors are not broken. Also verify lenses are clean and free of debris. In rare cases down force setting can trigger this same problem but this normally occurs at other door positions where more friction is encountered. A broken spring or cable jumped behind its pulley can exhibit same but the opener is actually operating correctly and going into safety mode. Avoid this confusion by testing door manually before troubleshooting the opener.

    If your motion sensors check good and door operates ok manually try turning down force dial clockwise, It is typically at 1 for a single width door or 3 for a double. Increase to 5 or 7 for test purpose. As doors get older their springs weaken. If you have increased down force threshold and the door continues to reverse, the RPM sensor is the culprit. There is no way to override or test this sensor by using the hand unit or the wall control. When this sensor goes bad the door will start down and the logic board will not receive the electronic pulses and it will reverse. It is this sensor that causes the door to reverse when it runs into something. The motor stalls, the logic board doesn’t receive these pulses and it reverses. This little circuit board is located at the door end of the motor shaft and every door company has them in stock. Take the cover off the unit and you will see a black cap on the end of the shaft that rotates between infrared sensors. That small circuit board is the culprit. Make sure you reinstall serrated cap so that as it turns it breaks sender receiver path on new board.

    first of all , thanks for a great web site.
    I didn’t think that a garage opener system could be so troublesome
    now my problem , the door is doing the classic , starts to go down then it (i assume it senses something ,and goes back up syndrome ) I checked my up/ down pressure adj , but cannot get it to complete a cycle . // then i thought , my sensors might be out of alignment , ( only one sensor is glowing // are both supposed be lit ?? i tried to adj so as both would lite up (thought when both are on that would tell me alignment is right on ) but no such luck. ///
    do i need a new sensor? // oh this is about a 9 year old sears unit it has worked fine except when it got reel cold one year -10 deg but after a little warm up worked fine again /

    Your receiver is not working – if transmitter failed you would have no lites. depending on model you may have wires that are preterminated and sealed inside sensor or the type you strip and either insert into hold while depressing spring holder or wrap around screw type terminal. check last types for broken wire or sometimes insulation gets too far inside spring holder type. try reterminating to insure contact is made in these types. If this does not help or you have sealed type wires move on to inspecting the feed wire back from the receiver looking for breaks or shorts – shorts can be caused by the very staples used to secure the wire – if staple looks suspiciously tight pull it out – if the staple has "broken" the wire you will need to solder or splice it. -if not sealed you can also remove unit and with some test wire hook it up over at the working unit so they both have power – not polarized- then face it into the sender to see if it lights.

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