How do I diagnose why our garage door remotes periodically stop working? I suspect that there is some sort of radio interference causing the problem.

This morning I left the house for about an hour. When I left, the opener worked fine. When I came back, the opener wouldn't work until it was about 3 feet from the antenna of the opener. I tested two remotes for this garage door, and two other remotes for two other garage doors. None of them would work unless inside the garage standing nearly directly beneath the opener.

This seems to happen every week or two. The interference seems to last for an hour or two. After that the garage door remotes start functioning normally again. I haven't been able to identify anything we are running inside the home that might cause it. I know that CFLs, microwaves, and such can cause interference. Often this happens when we get home when the house has been empty and pretty much everything in the house is off.

Our garage door openers are "Legacy" models manufactured by "Overhead Door" about 20 years ago. They use the "Code Dodger" remote control protocol. I have remote controls that came with the openers as well as universal replacements manufactured by Chamberlain.

  • Have you been able to determine if it is happening on the same day of the week and/or time? Commented Dec 21, 2015 at 18:52
  • No, I haven't been keeping track well enough. I should probably start keeping records which might come in handy for diagnosis. Commented Dec 21, 2015 at 19:02
  • This will help since from the scenario you set up places almost all of the blame for the interference on a source external from your house. Are you under any flight paths? Commented Dec 21, 2015 at 21:32
  • If this is new behavior, I'd check the antenna wire (if it has one) to make sure it hasn't gotten knocked off or looped up around the opener housing. Also, it's possible that after 20 years, your receiver is losing sensitivity -- it is possible to buy a replacement transmitter/receiver that uses more secure modern code rolling technology, since a 20 year old opener will use simple fixed code technology that can easily be hacked.
    – Johnny
    Commented Dec 21, 2015 at 21:38
  • 1
    @hopkins-matt I'm thinking it could be related to the heating system. That might explain why it is intermittent: it would be a problem only when the thermostat is calling for heat. Commented Dec 22, 2015 at 2:25

6 Answers 6


Excellent article! I just had my GDO remote drop from 30+ feet range to where I had to at the garage door - and it took several tries to cause the door to open. I had just installed a wireless indoor security camera and that was the culprit - unplugging it removed the issue. I tried various increases of GDO antenna length but no improvement. I was in the process of using a window screen on the opposite side of the wall when I found an article about an RFI kit - rather than buy the kit which was a tad pricey, I bought several 5mm ferrite cores that snap onto wires. 5mm based on the diameter of the wires they'd be used - they come in sizes 3mm to 9mm and possibly larger. I tried the camera power cord and there was no improvement - I then put a core on the manual switch wires where they connected to the GDO - that bought me another 8 feet of remote range. I then also added ferrite cores on the same wires near the manual switch and I'm out to 25 feet. The camera must be throwing off harmonics of the 2.4 GHz signal and the manual switch wires were acting as antennas. I'm still going to place the metal screen on the garage wall opposite the camera location in the house to try to block the RFI more yet. I hope this helps anyone with a similar situation as these cameras are more and more popular for nurseries, pet surveillance, and home security.

  • 1
    Hello, and welcome to Stack Exchange. Nice answer; hope to see more from you. Commented Aug 22, 2018 at 21:39

The national association for Amateur Radio (aka the American Radio Relay League or ARRL) has a PDF document about reducing radio interference. Among other things it suggests turning off the circuits in the house one at a time when the problem exists to narrow down the source of an device causing noise.

This Angie's List article has a list of common sources of noise that interfere with garage doors:

  • Nearby airports
  • Television or radio transmission towers
  • Military installations and ships cruising up and down the sound and ship canal
  • Power lines
  • Cell phone towers
  • Appliances within 10 to 15 feet of the receiver whether they are running or not.
  • Plug-in transformers like the ones used for security systems, sprinkler controls, and cordless power tool chargers.
  • Wireless doorbells
  • Computers
  • Wireless networks/Wi-Fi
  • Fax machines
  • Copiers
  • Cordless phones
  • Yard light timers and motion detectors
  • Christmas tree lights, especially LED (Light Emitting Diode)
  • Any number of small appliances. One of the most common culprits is cheap clock radios.
  • Air conditioning or heating system thermostats
  • Florescent lighting fixtures
  • Halogen lighting fixtures
  • Ham radio transmitters.
  • Car battery chargers
  • Motor Homes

Also, static charge buildups can cause the opener to malfunction -- this may be the problem if the opener malfunctions despite no other circuits in the hosue being on.


I had a similar problem. I have two garage doors with identical wall controls, remotes, operators. When my wife came back from the store today her remote would not open the door on her side of the garage. When I tried to come in my side also would not operate. The remote had worked when she left for the store earlier. The wall controls worked fine. I tried re-learning the remotes, but the learn LED just flashed constantly. I unplugged and replugged the openers, same problem. I wondered if a recent power spike had blown the receivers in both operators, but it had been working that morning.

I looked on the Internet for some ideas and found the operators manual for my remote (Linear brand). It only discussed blinking between 1 and 6 times. Nothing about blinking constantly. I found a dealers troubleshooting guide that did discuss this and said constant flashing was caused by RF interference. I called the tech support number in this guide and the guy said that I was being bombarded by RF interference.

At this point, I was asking myself how this could be happening. I had not changed any electronics or other devices that could do this. I started trying to isolate it by flipping breakers for appliances, etc. No change. There is a fairly new cell tower near us and I wondered if that could be it, but had no idea how I would determine if that was it.

I unplugged the operators one at a time to see if one was doing it to both of them. No luck. I took the batteries out of the remotes and the LED still flashed. I had an additional remote in the car for a gate opener for our driveway and when I took it off of the visor, the flashing stopped! I pressed the button on it and the flashing started again. I realized that this gate remote was being compressed behind the visor. My wife had used it to enter our gate on her return and I suppose she put it back on the visor in such a way that it compressed the button.

A simple cause for a bizarre problem.

Summary: The tech support guy was correct. My garage door operator was being bombarded by my gate opener remote in the car in the garage.


You may be able to check for 2.4Ghz interference by installing a WiFi router that uses 2.4 and connecting to it, then don't an internet speedtest at the suspect time. If your garage door opener uses that frequency...


This thread suggests isolating the garage door opener from interfering devices by placing a 3 foot x 3 foot square of aluminum foil on the ceiling above the opener.


i had a similar problem. my problem was the laser on the bottom of each side of the track. they are supposed to be pointed directly at each other and if something is blocking their line of sight, they door will not close properly. everytime my door doesn't close properly, there is usually a leaf blocking one of the sensors on the floor. might not be your problem, but worth a shot

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