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Garage Door Remote

Why doesn’t my garage door remote not work while the car is running? If I don’t move the car an inch and just shut off the engine the remote will work fine. I’ve switched remotes with my wife’s car and it works fine in her car but then hers does not work in mine. I’ve even left the car running and got out of the car with the remote in my hand and walked away a distance and it still would not work until I shut the car off. What is going on?

No doubt you’ve tried changing the remote fob’s batteries? Maybe they are old and the signal is weak.

If the fobs’ batteries are okay, I would think your car must emit a fair bit of interference in the frequency used for that remote. Maybe reposition the receiver’s antenna (it is usually a wire that’s just stapled somewhere) to see if that changes things.

What kind of car are we talking about here?

Yeah, I think radio signal interference of some kind from your car. Something on your car must be generating a radio signal at the same frequency as the remote and is interfering with it. You might want to just give the garage door opener company at call at their customer service line and see what they say about it. Might take a day or two but Chamberlain at least has technical troubleshooting staff that might be able to make a suggestion. I’d be running around with a sheet of tin foil trying to see if you can isolate where the interference is coming from. Don’t know if changing codes or not if you have them would help. The other thing is these things are all FCC compliant as well as cars so you may have something on the car that needs replacing and could interfere with other radio signals like police.

Can you tell us anything about the car?
That level of interference would suggest serious leakage from the ignition system. Either that or you bought the “International Spy” option.

“Either that or you bought the “International Spy” option.”

Hmmm, maybe check the trunk for a box with an antenna on it. Where’s that guy again that was being monitored in his car?

He’s out buying more tinfoil.

Years ago, my garage remote control would go up and down whenever the sewing machine was used. And the sewing machine wasn’t even in the garage. So electrical interference from your car is probably the cause. Making sure the batteries are fresh in the remote is a good idea, as well as making sure the antenna on the opener (if it has one) is fully extended. And try moving the remote around, compare the horizontal to a vertical orientation, see if that makes a difference. There are some ways to minimize the rf from the car too – like higher resistance spark plug wires — but if your radio seems to work ok on AM, I doubt that is worth trying.

You could try this too. Install a new remote operation on your existing garage door opener. This is easier and less expensive than it sounds. You know how you can make the door go up and down by pushing a button on the wall in the garage? Well, these gadgets connect to the opener at the same point as that push button. So they work by emulating the pushing of the button. But they come with a new remote control device that uses the latest rf encryption technology. This should be more immune to rf interference from your car, and make it less likely a thief might steal the code and open the door when you are away.

You might talk to ham radio people. They sometimes have to fight interference (RFI) with their radios that are used in vehicles. Possibly you can find a web site where they hang out. Search “AES radio” and call them to see what they might have to help. The main store is in Milwaukee but I don’t know which store has the best brain. Also, you could try a universal, programmable remote. A brand that I use is a Clicker two button model KLIK1U. It will cost you about $40 to find out if it helps. These are available online or at a home building supply store.

I’m a Ham and I agree…Something in your cars electrical (probably ignition) system is generating a signal that is swamping the garage door receiver so it can’t “hear” your remote…Does the AM band on your car radio sound okay or is full of a buzzing noise that changes pitch with engine RPM? A bad diode in the alternator will do the same thing…Remove the drive belt for a few seconds and see it that cures it…

Are we talking about a stand-alone remote, or the one built into the car, as many newer vehicles have? If a stand-alone, I’d probably change the batteries first, but I agree that it could be radio-frequency interference causing the problem. If built-in, it could be something wrong with the vehicle or a setting may be causing this behavior–I would consult the car’s owners manual in this case.

You got interference. aka, jamming from your car. Are you being bugged. Your remote should also be interfering with something in your car. Your garage opener should have a frequency listed somewhere on the opener.

Is your car a recent addition to your family? A newer vehicle? Built-in bluetooth or external devices with bluetooth.

@longprime: Bluetooth operates at a much higher frequency than any garage door opener I’ve seen. I can’t imagine that this would be the problem. If you get interference when the engine is running, I’d suspect you might have a bad ignition wire or coil-over-plug unit–something that is generating a lot of interference all over the spectrum. Certain kinds of alternator problems can cause a lot of RFI too. You may be able to check this by turning your radio to an unused AM station–if you hear regular ‘popping’ through the radio, suspect a failing ignition component. If you hear a whining sound that changes pitch with engine RPM, it could be the alternator. I suppose a third possibility is that one of the computer modules on the car is not properly grounded or shielded. Computers can generate a LOT of RFI if they are not shielded properly.

You may or may not be able to hear that sort of interference on a regular radio.

It could very well be that the interference is being generated by one or more of the on board computers.
They all need a clock to run. Whenever you generate a clock, it has a tendency to generate a multiple (“harmonic” or “spur”) of that clock as well, depending on how that thing was designed.
So it it runs off of a 20 MHz clock, you may see a spur on 40, 60, 80, 100, etc MHz.
Some of those harmonics could be suppressed just by the way the PC board is routed while others are actually stronger.
You have that, and when you have several clocks running, signals could very well mix either in the car or in one of the stages of a receiver.
When signals mix, you get the difference and the sum (and some other junk). It becomes an unholy RF mess. The FCC rules regarding unintentional transmitters allows for it because it becomes impractical to make sure junk is not transmitted on cheap equipment. It is more than just putting good shielding around things: signals have to be filtered, traces on boards should be of very specific design, off board connections need special consideration, etc, etc - I’ve been involved with this type of stuff for a living for years (actually, have also been a hamster since age 13). Designing so this doesn’t happen is not a walk in the park.
Rules change on military equipment where they spend a lot of time unintentional transmission is not happening. That’ can be really difficult to do so that’s why you pay 20K for a processor board you may pay $80 for, if you bought it from Dell.
Cars are considered consumer equipment so some of that junk transmission is allowed. Equipment is type approved, meaning they may test one to make sure it passes and all following are considered ‘passing the spec’ because the first one did.
It could very well be that your car somehow emits more than it should. It will be difficult to prove without a spectrum analyzer and their specification in hand. Dealers certainly aren’t equipped to even think of doing that.

Long story short:
it would be impossible to tell where those spurs end up in the frequency spectrum without a special analyzer. It is also pretty difficult to make sure those spurs aren’t generated on existing equipment, unless you’re willing to dig into it.
Just experiment with where that antenna is located. That’s easy to do and could help out.

Here’s a work around, if you know how to use a soldering iron:
You could hack up a box where you put your current remote into and hotwire the key press to a cheap gate opener receiver* you put in that box as well. You can get one for maybe 20 bucks on ebay. Or, if your garage door opener has a hard wired button, wire that button to that cheap gate opener.
You may have to open your current remote and wire its ‘open’ switch to the gate opener’s contacts, if you don’t have that wired button.

You then carry that gate opener remote on your car.
There’s a good chance it isn’t on the same frequency so when you press its button, it ‘presses’ the button of the garage door opener or the wired button.
Your wife can just use the remote she uses now.
Hey, maybe we should market this idea, if this ends up being a real problem! Call it the garageDoorRepeater!

Here’s a cheap one:

Garage door openers operate between 300MHz and 400MHz. But their protocols do vary by manufacturer and model.

Perhaps a new garage door opener is the answer.

the guy is so cheap, he needs to post on CarTalk. I had this problem with a house we were watching-the owner had messed with the tuning coil. Spent $20 for a battery from dealer which of course didn’t solve the problem-ended up paying $70 for a new unit.

Personally, I like my supposition that he’s being bugged.

“Personally, I like my supposition that he’s being bugged.”

Triedaq claims that many of us have had chips imbedded while we were asleep so maybe that’s it. Works for the wife because she doesn’t have a chip yet. Maybe the wives are the ones behind this so they know where we are and can program our thoughts too. Where do ya get that spectrum analyzer?

From ‘spectrumAnalyzers_R_us’ their number is…

…can’t talk right now; my wife walked in. She is pressing a button on some sort of remote and I now have this sudden urge to rub her feet…

Essentially all the receiver for the remote does is complete a circuit or “connect two wires together” briefly to trigger the opener when it receives a properly coded signal from the remote.

So instead of turning this into a major project, you can just ‘add on’ another receiver/remote pair that might work better. You can continue to use the existing system as well.

Here is a receiver/remote combo that I use with the ancient Genie garage door openers I have. It’s tiny and has two channels. The range isn’t spectacular, but plenty adequate, and it works well. It also works fine with the integrated universal remote built into my 2006 Chrysler vehicle, that ‘learns’ garage door remotes.

I actually had one of these for tinkering before purchasing my home. I had patched it into the door buzzer for the apartment I used to live in so I could key the remote and it would buzz me in the front door of the building.

FYI, the receiver part of the combo below simply plugs into an electrical outlet. You won’t need a project box, power supply, or anything fancy. Just select the security code you want to use, connect two wires, plug it in, and good to go.