How Garage Door Remote Works (Info& Troubleshooting)


Ever wonder how the remote control for your garage door actually works?

Garage door remotes work by sending a coded signal via radio frequency to the garage door opener motor. If this code matches that of the motor, it will start to raise or lower the garage door.

There are many more features too. Let’s look at the basics first and do troubleshooting if the remote is not working.

The History of Garage Door Remotes

Wireless garage door openers were invented in the US. The first openers were very simple. When two neighbors had garage door openers, then opening one garage door might open the neighbor’s garage door as well.

Later manufacturers added simple codes. The garage door would only open if the receiver’s code were the same as in remote. This provided some level of security, but not much.

Modern systems use rolling/changing codes which means the code used is different each time the door opens or closes. And other security features that are very secure.

Thanks to the rolling code method, it’s impossible for your transmitter to open another garage door or vice versa. More recent systems include more codes, as well as longer codes. The more recent your system is, the less likely it is for another transmitter to open your garage door.

Today, garage door openers are unbreakable when it comes to code hacking and pirating.

The Basics of Garage Door Remotes

The remote contains a radio transmitter. The opener motor has a receiver built into it. When you press the button, a radio signal is sent from the remote to the opener/receiver. Most openers use a specific frequency in the range of 300-400MHz.

The controller chip in any current controller uses a hopping code or a rolling code to Increase security. For example, a system that uses a 40-bit rolling code. Forty bits provide about 1 trillion possible codes. Here’s how it works:

  • The transmitter’s controller chip has a memory area that holds the current 40-bit code. When you push a button on your fob, it sends that 40-bit code along with a function code that tells the car or door motor what you want to do. (open the doors, lock the doors.)
  • Both the transmitter and the receiver use the same random number generator. When the transmitter sends a 40-bit code, it uses the random number generator to pick a new code, which it stores in memory. On the other end, when the receiver receives a valid code, it uses the same random number generator to pick a new one. In this way, the transmitter and the receiver are synchronized. The receiver only opens the door if it receives the code it expects.
  • If you are a mile away from your garage or car and push the button on the transmitter, the transmitter and receiver are no longer synchronized. The receiver solves this problem by accepting any of the following 256 possible valid codes in the random number sequence.
  • This way, your child could push a button on the transmitter up to 256 times, and it would be okay — the receiver would still accept the transmission and perform the requested function. But, if you push the button 257 times, the receiver will ignore your transmitter. It won’t work anymore.

So, what do you do if your child DOES desynchronize your transmitter by pushing the button on it 300 times so that the receiver no longer recognizes it? Most cars give you a way to resynchronize. Here is a typical procedure: also you can check your car manual.

  • Turn the ignition key on and off eight times in less than 10 seconds. This tells the security system in the car to switch over to programming mode.
  • Press a button on all the transmitters you want the car to recognize. Most cars allow at least four transmitters.
  • Switch the ignition off.

Given a 40-bit code, four transmitters, and up to 256 levels of look-ahead in the random number generator to avoid desynchronization. There is a one-in-a-billion chance of your transmitter opening another garage or car door.

When you consider the fact that all manufacturers use different systems and that the latest systems use many more bits, you can see that no given key fob can open any other car door.

You can also see that code capturing will not work with a rolling code transmitter like this. Older garage door transmitters sent the same 8-bit code based on the pattern set on the DIP switches. Someone could capture the code with a radio scanner and re-transmit it to open the door.

With a rolling code, capturing the transmission is useless. There is no way to predict which random number the transmitter and receiver have chosen to use as the next code, so re-transmitting the captured code has no effect. There is also no way to scan through all the codes with trillions of possibilities because it would take years to do that.

How to Know Which Type of Garage Door Opener Remote to Buy

Extra garage door opener remotes come in handy; but, choosing the suitable opener can be confusing. Each manufacturer makes its replacement remotes, and universal remotes are also available.

You must decide the features you need and the size of the remote. Full-size remotes clip onto the car visor. This is convenient; yet, it may become a security risk if your car is stolen. Mini-remotes clip onto your key chain and operate like a full-size remote.

Find the Garage Door Opener Information

Look for the manufacturer and model information on the motor unit found on the garage ceiling.

Using the manufacturer information, you can buy an exact replacement for the garage door remote by matching the brand and model number. Then you can buy it from a representative of the manufacturer, your local hardware store, or online.

If you have an older garage door opener, this is the way to go. Many universal remotes do not work on older models, but the manufacturers still sell the remotes.

Universal Garage Door Remote Controls

Universal garage door remote controls are available that you can program for use with most brands of newer garage door openers. You still need to know the manufacturer to make sure the remote works for your garage door and program the remote.

You can program universal garage door openers to open one or two garage doors. With the addition of a light control switch, a universal remote also turns on the garage light or your home lights. Suppose you have a more recent garage door opener, but you are unsure of the exact model. In that case, a universal remote will do the trick.

The Garage Door Remote Buttons

The number of buttons on your garage door remote is determined by how many devices you want to control. If you have two garage doors and a remote-controlled garage light, you need three buttons. One garage door and one light or two doors require two buttons. Garage door remotes are available with up to four buttons.

Programming the Garage Door Remote

If you buy the remote for your particular brand of garage door, programming is usually simple. You press, hold, and release the buttons in the pattern specified in the instructions. The remote will determine the correct radio frequencies for your garage door opener.

Universal remotes are a little more complicated. You have to first set the dip switches on the remote to state the garage door opener brand, then the radiofrequency. Your universal remote should come with programming instructions.

Garage Door Wireless Keypads

You can also replace a garage door opener with a wireless keypad. Wireless keypads can open up to three different gates or garage doors and are usually mounted outside the garage so that family members can open the garage without the remote.

Wireless keypads need a security code to open the garage door. They are convenient if you have lost or forgotten your remote and for use by temporary guests or service persons.

My Garage Door Remote is Not Working

Troubleshooting tips for when your garage door remote stops working or the buttons are not responding.

Garage Door Remote Batteries Are Depleted

Do you remember the last time you replaced the batteries in your opener remote? If your garage door opener remote has stopped signaling for your door to raise and lower. Consider whether the batteries have died before calling your local garage door repair professionals.

Garage door remote batteries typically last about two, three years before needing to be replaced.

To check if your transmitter batteries are dead, try using your wall-mounted control panel to open the door. If the door responds, then dead batteries are likely the cause.

Replace the Garage Door Remote Batteries

  1. The most common cause for remote not working is dead batteries. So, check the batteries first!
  2. Access the batteries by opening the panel on the back.
  3. If your device has screws, remove them, and open the panel.
  4. Take the batteries out.
  5. Check the battery contacts. If they look worn out, dirty, or wet, clean and dry them before putting the batteries back in.
  6. Replace the batteries. Depending on your remote, it can use either small, round batteries, AA, or AAA batteries.
  7. Reassemble the remote.

Garage Door Remote Signal Disturbed 

After placing fresh batteries in your remote, if the door still won’t respond, then the signal between the remote and opener transmitter may be disrupted. Two common causes for a signal interruption are if your remote is out of range or the opener receiving antennae is damaged.

Stand within 20 feet of your garage door and attempt pressing the button — if your remote is further away from the door, the signal maybe won’t be strong enough to prompt the door.

If your remote works, check that the opener’s antennae don’t have any excess debris buildup, is pointed toward the door, and isn’t broken. If the antennae appear to be damaged, call your local repair professionals to inspect the problem and make repairs.

Garage Door Lock Button Engaged 

Another simple garage door fix is to make sure the lock button on your garage door’s wall-mounted control panel hasn’t been engaged. You could accidentally press this button while performing normal daily activities. You can disengage the door lock by pressing the lock button. After unlocking the door, test the door’s operations by pressing the panel’s open button.

Garage Door Remote Needs Reprogramming

Before calling your local garage door repair technicians to inspect your malfunctioning system, you can also try reprogramming your garage door remote to the opener. Sometimes, with regular use, the signal between your opener and remote can be disrupted and need reassociation.

To reprogram your garage door remote, locate and then press your opener to learn button. Then, within 30 seconds, hold the button on your remote for three seconds or until the garage door opener’s lights flash, or the LED light on your opener blinks.

  • Try using your remote to open or close your door to determine if the reprogramming was successful.
  • Sometimes the remote may need to be reprogrammed.
  • Check the remote’s user manual or visit the manufacturer’s website for instructions on how to reprogram the remote.

Usually, all you need to do is to pair the remote with the opener by holding down the open button on the remote while pressing the programming button at the same time. Next, release the open button when the garage door opener light starts flashing.

Garage Door Opener Not Installed Properly 

If the remote and wall-mounted panel method doesn’t raise or lower your door, then you may have a problem with your garage door system’s control wiring or the opener’s receiver board. If this is the case, call to have an expert reprogram and install your garage door opener.

GFCI Needs to be Reset 

Another common reason your garage door remote control might not work is because of a blown Ground Fault Circuit Interpreter (GFCI). A GFI handles protecting your home from any potential electrical dangers, such as overheating.

Suppose you’ve ever been using your hairdryer and have to hit the reset button on your wall outlet. You’ve experienced your GFI jumping in to prevent you from blowing a fuse.

About your garage door, a malfunctioning GFI would generally stop the door from functioning at all. Or might start using the back-up battery in some models.

You can fix a blown GFI by pressing the reset button on the wall outlet that corresponds with your garage door—usually located in the garage, laundry room, or main bathroom.

After following the above troubleshooting tasks, if you find your garage door still will not respond to commands.

Contact a professional garage door technician to inspect your system and recommend repairs or hardware replacement.

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