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Automatic Garage Door Opener Ultimate Repair Guide!

Table of Contents

  1. Introduction.
  2. Garage Door Sensors.
    1. Most common sensor problems and how to resolve them.. 
      1. Initial test. 
      2. Clean regularly. 
      3. Check the wires. 
      4. Short wire test. 
      5. Sensor alignment. 
      6. Deformed sensor mount. 
      7. Natural causes.
    2. Replacing the automatic garage door opener sensors.
      1. Disconnect the power.
      2. Remove the sensors. 
      3. Connect the new safety sensor wires.
      4. Install, reconnect and line up the safety sensors.
      5. Final Test. 
  3. Remote control, wireless keypads and wall switch. 
    1. Most common problems and how to resolve them..
    2. Check the range. 
    3. Check for damages. 
    4. Wall switch malfunction.
  4. Power issues. 
    1. Test the electricity. 
    2. Replacing the circuit board. 
    3. Replacing the light socket. 
  5. Improper garage door movement. 
    1. Replacing an old unit. 
      1. Tools and materials. 
      2. Removing the unit from the gear shafts. 
      3. Removing the helical and worm gears. 
    2. Replacing the trolley carriage.
    3. Replacing the main gear drive.
  6. General adjustments.
    1. Check the chain tension.
    2. Adjust the door travel 

garage door opener repair guide


For the last several decades, we have witnessed an unbelievable evolution of automated garage doors. The drastic change from slow and rigid doors to high-speed and automated ones has brought about incredible strides in the areas of increased energy and productivity savings, as well as higher level of safety.

Although the design of the automatic garage door openers has improved significantly, according to the statistics compiled by the Consumer Product Safety Commission, staggering 40% of safety systems fail to work due to automatic garage door openers breakages. In order to ensure the utmost level of security for your family members, regular maintenance is highly essential. Nevertheless, despite all efforts, automatic garage door openers are still prone to malfunction and the following guide lists the most common problems known to occur with both residential and industrial garage doors.

Garage Door Sensors

In an effort to improve the quality of living and lower the number of deaths caused by automatic garage door openers, the U.S. Consumer Product Safety Commission issued final rules on December 3rd 1992 regarding the automatic residential garage door openers. The rules which were issued in the Federal Register included revised entrapment protection requirements for all automatic residential garage door openers manufactured after January 1st 1993 for sale in the US.

The rules published more than two decades ago specified further entrapment protection requirements, and the revised standard now requires that all garage door openers contain the external entrapment protection device known as the “electric eye”. This handy feature enables the garage doors to register if there is an object standing in a way. What happens is that one of the sensors sends an infrared bean, whereas the other one receives it. If there is an object breaking the beam, the garage door will stop closing and reverse the direction.

By taking all of this into consideration, it is highly advisable for all users to test the automatic garage door openers according to specific manufacturer’s recommendations.

Most common sensor problems and how to resolve them

There are a multitude of issues that might occur in relation to the automatic garage door opener sensors. In the following section we have listed some of the most common ones and the ways to address them.

Initial test

It is highly advisable to regularly check if the sensors work1 properly by putting an object in their way and trying to close the garage door. If they close despite the obstacle you’ve placed, it means that the sensors are not functioning.

Clean regularly

First off, use a clean rag to remove any debris or dust from the electric-eye lenses on both sensors. If the problem is still present, move on to inspect the wiring.

Check the wires

To do so, check between the sensors and the garage door openers to see whether there’s incorrect wiring. The solid white wire should be connected to the white terminal and the white/black ones to the gray terminal.

Short wire test

If the wires are in place, move on to remove sensors from the brackets and the wires from the wire nuts, or simply cut the sensor wires 12’’ from the sensors. Next, strip both ends of the wires from both sensors and twist the wires of the same color together. Take both sensors to the garage door opener motor unit and remove the existing wires from the white and grey terminals on the back of the operator. Insert white wires from white and gray terminal on the back of the operator and point the two sensors at each other. If both LED lights are lit, wiring is the source of the issue and the wires between the opener and the sensors should be replaced. However, if the LED lights don’t light up, then you should replace the sensors (see the instructions below).

Sensor alignment

In some cases, you might notice that LED lights are dim, flickering or completely off, which means that the safety reversing sensors are not aligned. To fix this issues, remove the LED light from the bracket by taking off the wing nut and then point the receiving sensor away from the sending one to ensure that the LED light is completely off. Wait about 10 seconds before slowly rotating the sensor back until it lights up green again. Once you’ve fixed it, return the green LED light back into the bracket and put the wing nut back on.

Deformed sensor mount

It can also happen that your automatic garage door opener comes with a bent or deformed sensor frame on either side of the system, thus preventing the light beam from being transmitted. These sensor mounting brackets are usually made of aluminum, what makes them fragile and easy to distort with a bike, ladder or any homeowner’s tool. Nevertheless, the fact that they are made of soft aluminum works to your advantage since then it can be easily bend back by hand.

Natural causes

The sources to some of the problems might not be necessarily routed in the sensors or caused by human error. For example, if the receiver is in the direct sunlight at any time you attempt to open the garage door, the system might not work. In that case, unplug your garage door opener from the ceiling and swap the places of the transmitter and the receiver. Important: Remember to swap the wire connections on the opener as well.

Replacing the automatic garage door opener sensors

If it happens that a safety sensor is malfunctioning and this is the first time you are facing a problem of this kind, you first need to detect the exact nature of the problem. To troubleshoot the safety reversing sensor, ensure they are connected and aligned correctly before the garage door opener moves in the downward direction. Most commonly, issues regarding the automatic garage door openers occur due to a poor connection, incorrectly connected wires or a short in the wire from a staple.

If you’re looking to fix the sensor issue on your own, make sure you have the following tools:

  • Pliers
  • Wire cutters
  • Blue wire nuts
  • Step ladder

However, before you begin, put on work gloves and safety glasses. DIY repairs can be quite hazardous, especially if done by a non-professional. It’s important to remember that under no circumstances should you begin with the repairment process before reading all the steps and ensuring that you understand every single one of them.

Disconnect the power

Prior to doing any work around the automatic garage door opener, it’s essential to disconnect the power. If it happens that the power cord and motor unit are difficult to access, use the ladder to unplug it.

Remove the sensors

Next, remove the wing nut from the safety sensor and pull the sensor from the bracket. Cut the wires about an inch from the safety sensor, but make sure you leave enough slack in the control wire to connect the new sensor. The process is the same for the other sensor.

Connect the new safety sensor wires

Take the new sensor and separate the control wires. Find the black-striped control wire and connect it to the black-striped safety sensor with the crimp wire nut. Do the same with the white wires and repeat the entire process with the other safety sensor.

If you decide not to use the crimp wire nuts that come with the new safety sensors, you can easily strip ½-inch of insulation from each wire and connect the wires using wire nuts.

Install, reconnect and line up the safety sensors

Take the new sensor, slide it into its bracket and secure with the wire nut. Finally, plug in the garage door opener and align the safety sensors so that the green indicator light on the receiving sensor glows steadily.

Final Test

To make sure the garage doors are fully functional and don’t present the safety threat to your family, never skip the testing process. First, open the garage door and place a certain object between the safety sensors so that they block the sensing beam. Attempt to close the garage door with a remote. If they stay opened, you did a good job, but if they close, replace the logic board or consider ‘calling the guy’.

Remote control, wireless keypads and wall switch

Around 50% of homeowners report using a remote control or wireless keypad to operate their garage door. According to their specific functions, we can classify garage door remote controls into several types:

  • Universal remote controls, popular because of their compatibility with most of the newer brands of automatic garage door openers. Universal remote control can be programmed to open one or two garage doors, depending on your specific needs. Certain types of universal remote controls feature a light control switch allowing you to turn on and/or off the lights in your garage or home.
  • One-touch button remote controls can be programmed to control only one garage door or one garage door light.
  • Multiple-button remote controls are suitable for residential and industrial garages with two or more doors and lights.
  • Wireless keypads can open up to three different garage doors and are most commonly set outside the garage door. To control the garage door with a wireless keypad, user is required to enter the security code.

Most common problems and how to resolve them

A number of remote controls feature LED lights which alert you if any of the problems occur with garage door or the remote control.

Check the range

The most common source of the remote control problems is the range in which it operates in. Even though they are wireless, if you are not in the range of the IR signal-sending strength, the remote control will not be able to open or close the door. Also, don’t forget to check the batteries.

Check for damages

Furthermore, it can happen that the remote control gets slightly damaged. For this reason, check the plastic covering of the IR unit on the remote control and the receiving unit. As the IR signal is supposed to pass through it, even the slightest damage or a thin layer of dust can prevent it from proper functioning. Simply take a damp cloth and polish the plastic covering from time to time.

Note: Plastic coverings are fairly resistant to scratching, but if it happens that they get rubbed against the metal or abrasive fibers, you can opt for specialized plastic polishing substances. In case the damage is permanent, the only option is to replace it with a new one.

Wall switch malfunction

If the remote control and wireless keypad work properly but the wall switch does not, you will either have to switch the wires or replace the entire device. In order to determine which of the two wires from the switch is not working, unscrew the switch from the wall and touch the wires together (due to a low voltage, the test is not hazardous). If the opener runs, it means that the switch is broken, but if it still doesn’t run, you will need to use a small wire and jump the wires at the opener terminal. If the opener reacts, it means one of the wires is the cause of the problem.

Power issues

A fair number of issues regarding the automatic garage door openers occurs due to the lack of power, but it is also possible that certain parts of the automatic garage door opener break after a particular time period.

Test the electricity

If your garage door doesn’t respond to either the remote control or the wall switch, it can happen that the unit is not receiving enough power to operate properly. First, try turning the lights on and off. If there is no response, check to see if the motor unit is connected. If yes, it is possible that the outlet is not working, so test it with a different appliance. Finally, if all else is functioning properly, the source of the problem can be a circuit breaker, so fuse or ground fault circuit interrupter.

Replacing the circuit board

If there is power but still no lights or sound after trying to operate the garage door via remote control or a wall switch, you might be looking at a broken circuit board. Replacing it might sound challenging, when in fact it doesn’t take more than 10 minutes and all you need from your toolbox is a ¼-in. nut driver. Start by removing the light cover, then take out the light bulb and disconnect the switch and the safety sensor wires. Finally, just remove a few screws and unplug the board.

Replacing the light socket

If even after replacing the light bulbs they still don’t lit up, it is highly likely that the light socket is broken. To replace it, you will first have to remove the circuit board (follow the instructions above). Once it is removed, pop out the old socket by depressing the clip that holds it and remove the two wires.

Note: Always chose the lightbulb of the appropriate wattage (equal or lower than the socket) to prevent the socket failure.

Improper garage door movement


Although some of the most reputable automatic garage door openers manufacturers strive to design state-of-the art products that will meet everyone’s needs, the fact is that you are likely to encounter numerous issues regarding particular parts of the device. From faulty motor or main drive gear to cables snapping, different issues might cause improper garage door closure, so check out the next section for DIY repair tips.

Replacing an old unit

If the door stays closed but you can hear the grinding noise, check the plastic gear that is in direct contact with the worm drive gear on the motor. Before tackling the issue, note that the replacement is quite difficult and first go through all the steps listed in the next section to ensure you understand each and every one well enough to do it yourself. If not, turn to an expert.

Tools and materials

In order to rebuild a garage door opener in less than two hours, you will need the following tools:

  • 4-in-1 screwdriver
  • Hammer
  • Cordless drill
  • Circular saw
  • Socket/ratchet set
  • Adjustable wrench
  • Allen wrench
  • Wrench set
  • Small drift punch
  • Flashlight
  • Rags
  • Gloves
  • 2×4 x 2’
  • Replacement gear kit
  • Chan grease


Removing the unit from the gear shafts

First step involves removing the chain, so unscrew the outer nut on the chain tensioning rod. If the chain starts turning, use pliers to keep it in place. Next, put on the gloves and remove the chain from the sprocket at the top of the opener.

You will need the combination wrench to loosen and remove the chain, and a ¼-in. drive socket, extension and ratchet to remove the helical gear assembly retaining screws. Next, disconnect the motor wires, remove the motor assembly and put it together with the helical gear assembly on your workbench.

Removing the helical and worm gears

Start by supporting both ends of the helical gear assembly with the two jigs. Hold a drift punch over the roll pin and then tap the pin out with a hammer. Next, pick up a circular saw to cut a shallow groove into a 2×4 and slice off about a 3-in. section to make a jig that will hold the helical gear assembly circular plate. Take the plate and place it in the groove, hold the gear assembly level and mark the end of the shaft on another 2×4. Then you will have to drill a hole in the wood and insert the end of the shaft. Remove the roll pin, slide off the old gear and replace it with the new device. To reinstall the toll pin, you can use the same jigs.

Remove the retaining collar and thrust washers on the end of the motor shaft. Pull the motor out of the chassis and slide the gear off the shaft so that the notched end faces the roll pin. Finally, reassemble the motor assembly and place it back in the opener. Install the helical gear assembly and coat the gear teeth with new grease.

Replacing the trolley carriage

On some instances, the trolley carriage moves but the door still doesn’t open, meaning that the trolley carriage is broken. First, clamp down the chain to the rail to maintain the location of the chain on the sprocket and speed up reassembly. Once the chain is set in one place, separate it from both sides of the trolley and disconnect the rail from the header bracket. Then you will be able to slide off the old trolley and put the new one. Finally, reattach the chain and adjust the chain tension.

Replacing the main gear drive

If you hear your garage door opener making a grinding noise but your garage door doesn’t move, it’s highly probable that the main drive gear is faulty. In order to get to it, you have to remove several components first. So follow the steps for the replacement of the old unit listed above and then you will be able to get the main gear drive out with a punch.

General adjustments

In some cases, it can happen that certain parts have not been properly set, what eventually leads to an automatic garage door opener failure.

Check the chain tension

With most automatic garage door openers, you are supposed to tighten the chain so there is about ¼ in. to ½ in. of slack from the rail to the chain. Check the manual that came with your model of automatic garage door opener to set the ideal tension. Overtightening can put excess wear and tear on the shaft and wear, whereas not enough tension will cause the chain to skip off the sprocket and fall.

Adjust the door travel

If there is an upward bow in the rail, it means that you need to reduce the distance the door travels down. Check the opener to find the two knobs that control how far the door travels up and down. Adjust the door so that they press tightly against the garage floor so the weather stripping seals the gap. If the door travels too far, it can cause excess wear and tear on the shaft and gear, as well as create the upward bow on the rail.

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