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Discussion Starter · #1 ·
Has anyone taken the homelink buttons apart and found a way to make the homelink only available only when the the battery is on. There have been a rash of thieves breaking into cars and opening garage doors with the homelink. I did it on our toyota and just found an an ignition switchable wire and tapped into that. Just wondering if anyone has done this yet with some pointers.
 

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Has anyone taken the homelink buttons apart and found a way to make the homelink only available only when the the battery is on. There have been a rash of thieves breaking into cars and opening garage doors with the homelink. I did it on our toyota and just found an an ignition switchable wire and tapped into that. Just wondering if anyone has done this yet with some pointers.
I also have this concern. I hadn't yet verified that the headliner buttons were active with the vehicle "off", by leaving a passenger in the car to test it, after I've left it for a few minutes and took the fob out of range. Did you do this to verify Homelink still functioned with the vehicle off?
 

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when I have added a mirror with Homelink to other cars they have you tap into a hot wire, so it is always on. Since I always park inside my garage it would be pointless to change it, plus I don't know how long the flash memory lasts if you have it turned off frequently.
 

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Has anyone taken the homelink buttons apart and found a way to make the homelink only available only when the the battery is on. There have been a rash of thieves breaking into cars and opening garage doors with the homelink. I did it on our toyota and just found an an ignition switchable wire and tapped into that. Just wondering if anyone has done this yet with some pointers.
My question is: what is the process by which this happens? Do the thieves break into the car, steal the Homelink, and then reactivate it to break into your house? Or do they not steal anything physically and simple carry a device which records the codes which are then retransmitted later when they break into the house? Either way, if they are smart enough to do either of these things then I’d imagine they may be smart enough to override or bypass a Homelink that is only powered up when the ignition is on.
 

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My question is: what is the process by which this happens? Do the thieves break into the car, steal the Homelink, and then reactivate it to break into your house? Or do they not steal anything physically and simple carry a device which records the codes which are then retransmitted later when they break into the house? Either way, if they are smart enough to do either of these things then I’d imagine they may be smart enough to override or bypass a Homelink that is only powered up when the ignition is on.
Meth-heads looking for money to buy their next bump usually don't posses an electrical technician certificate. I look at the scenarios you've outlined as exceedingly unlikely series of actions.

HomeLink garage-door opener buttons are commonly on the headliner, and a simple push of a button usually opens the garage door. I'd expect that a meth-head might push the buttons many times, but without a garage door opening in response, they'd likely move on to the next house.
 

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when I have added a mirror with Homelink to other cars they have you tap into a hot wire, so it is always on. Since I always park inside my garage it would be pointless to change it, plus I don't know how long the flash memory lasts if you have it turned off frequently.
I've added my own custom garage-door opening circuits to all of my vehicles for at least 30 years.

I run a wire from the headlight brights wire to one add-on relay's coil connection. The other side of the relay coil is attached to chassis ground. I find an unused ignition-switched power source in the fuse panel and route it through the relay contacts, then I wire it to a simple zener regulator circuit that's set to the battery voltage of a garage door remote battery. (A simpler voltage divider works, too. I'm an EE, so have zeners and resistors lying around.) I modify a garage door remote to have the "push to open" button shorted to be "on" always. I solder a wire to the negative battery terminal in the remote and attach it to a handy chassis ground point, I then solder the zener-regulated circuit's output wire to the remote's battery positive terminal. Dress the wires, sync the remote to the opener and Velcro the remote to the top of the fuse box (or hide it in the engine bay).

A simple pull on the brights will open my garage door, but the vehicle has to be "on" for it to work. The rolling-code garage door opener system doesn't care, because it can handle at least a hundred activations outside of it's normal usage and still retain sync. I rarely use the brights outside of opening the garage door, so this has never been a problem.

I actually prefer this to the Homelink solution because of the security issue of Homelink buttons working with the vehicle "off". I'll be testing the Homelink system in the Clarity, to verify that it's "always on". If it is, I'll certainly try to power it with an ignition-switched source instead, and if that's not practical, I'll likely do the mod I've outlined above. My Clarity lives in the driveway. My wife's Bolt gets the garage. "Happy wife, happy life" and all that.

One downside is the potential wear-and-tear on the brights light bulbs. FWIW, I've never had to replace the headlights on any vehicle I've done this to. I've done this on motorcycles as well. I also am careful not to flash brights at neighbor's houses when I come home at night.
 

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Discussion Starter · #7 ·
The thieves here break window or jimmy door open while the car is parked in the driveway or on the street in front of the house. They push homelink button because it is on without the key and open garage and enter house to do as they please. With my toyota, I was able to cut one wire and make it so it was only on with ignition on.
 

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The thieves here break window or jimmy door open while the car is parked in the driveway or on the street in front of the house. They push homelink button because it is on without the key and open garage and enter house to do as they please. With my toyota, I was able to cut one wire and make it so it was only on with ignition on.
Oh, I think I understand now. So they’re breaking into the car which is sitting in the driveway in order to gain access to the garage. So the takeaway is don’t leave your car parked in the driveway. Put it away in the garage. Right?
 

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Oh, I think I understand now. So they’re breaking into the car which is sitting in the driveway in order to gain access to the garage. So the takeaway is don’t leave your car parked in the driveway. Put it away in the garage. Right?
Not always possible. In my case, a different vehicle is in the garage, along with a motorcycle and e-bikes. The Clarity lives in the driveway. A lot of people don't even have garages.

IMO, having Homelink always active is a major goof.
 

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Discussion Starter · #10 ·
It never dawned on me to park in the garage...thanks for the solution Dave..very helpful!

I was just putting this out there to see if we have anyone handy in tracing wires to see if there is maybe one wire that can be cut to make it ignition switchable powered. I pulled the module down from the roof. It looks like the homelink wiring is bundled in with some type of other sensors.
 

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It never dawned on me to park in the garage...thanks for the solution Dave..very helpful!

I was just putting this out there to see if we have anyone handy in tracing wires to see if there is maybe one wire that can be cut to make it ignition switchable powered. I pulled the module down from the roof. It looks like the homelink wiring is bundled in with some type of other sensors.
Not a solution. Just an observation since I didn’t understand the situation from your original post.
 

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Not always possible. In my case, a different vehicle is in the garage, along with a motorcycle and e-bikes. The Clarity lives in the driveway. A lot of people don't even have garages.

IMO, having Homelink always active is a major goof.
I wasn’t trying to be sarcastic or anything. I was just mentioning that for certain people (like me) the takeaway is to not leave your car parked in the driveway. I realize that some people don’t have the luxury of having enough garages to stow all of their vehicles.
When I read the original post I was unaware of the method which thieves were using. The OP didn’t describe that the car is being broken into right in your own driveway. That being said, I agree that the ‘always on’ Homelink is probably not the best idea. However, I don’t believe it’s just Honda that does this. I’ve used other cars where it would work with the car turned off. If nothing else, it should probably be an option that the owner can select (Homelink with power off or not).
 

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I think I have a solution that doesn't require any permanent mods to the Clarity, and in fact might work for any vehicle. It requires use of two "Add-a-Fuse" devices, and knowledge of which always-on fuse location feeds Homelink and another fuse location that's on an ignition-switched power feed. In an ideal world, you'll find an empty position in the fuse panel that has ignition-switched power going to it. I've identified the Add-a Fuse devices as (1) and (2).


Verify that the vehicle is "off".

Remove the fuse in the fuse panel that feeds Homelink. In one Add-a-Fuse (1) device, leave the primary fuse location EMPTY and place the removed Homelink fuse just removed in the Add-a-Fuse (1) added circuit fuse location. Plug this Add-a-Fuse (1) device into the Homelink fuse panel location, but plug it in BACKWARDS. The dangly wire on this Add-a-Fuse (1) now goes to the side of the fuse location that feeds the Homelink circuit. Measure the voltage on the dangly wire of the Add-a-Fuse (1) to be sure. If you find 12V there, it's not plugged in backwards...flip it around and measure it again. It should measure as 0V.

If you're following along here, you may have figured out what I intend to do...

Remove the fuse on the identified ignition-switched circuit (if it's not an empty location). In the other Add-a-Fuse (2) device, leave the primary fuse location empty (for now). In the added fuse location of this Add-a-Fuse (2) device, place a fuse in there that's the same value as the one removed from the Homelink-feeding circuit. Plug this Add-a-Fuse (2) device in the ignition-switched circuit location. Measure voltage on the dangly wire. It should be zero.

Verify that neither dangly wire is touching anything, and turn the vehicle "on"

At this point, the Homelink and ignition-switched circuit identified should still be dead, and it's possible that the vehicle will throw a code or two. Somewhat expected...

Measure voltage on Add-a-Fuse (2)'s dangly wire. It should be 12V. If it's not, turn off the vehicle, flip Add-a-Fuse (2) around and turn the vehicle back on. Again measure voltage on Add-a-Fuse (2)'s dangly wire. It should now be 12V.

Turn off the vehicle.

If you are using an ignition-switched location in the fuse panel that had a fuse in it, do the following. Otherwise skip down to the dashed lines.

Remove Add-a-Fuse (2) and because you took a fuse out of that position, place that fuse in the primary fuse position of Add-a-fuse (2). Plug Add-a-Fuse (2) back in the location you just took it out of, with the same orientation it just had.

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What you now have is a dangly wire from Add-a-Fuse (1) that is the feed to the Homelink circuit, and a dangly wire from Add-a-Fuse (2) that only has 12V when the ignition is "on". If you tie these two dangly wires together, the Homelink circuit will only have power when the ignition is "on". So...

Cut off the crimp connector from one of the Add-a-Fuse devices. (It doesn't matter which one.) Strip that wire, and crimp it to the dangly wire attached to the other Add-a-Fuse device.

Done.

Caveats:

You need to know which circuit fuse location goes to Homelink.
You need to know which fuse locations have ignition-switched power going to them.
You need to know which other devices in the vehicle are fed from the same circuit as Homelink,
and how they would respond to intermittently cutting power. (Quite important.)
Screwing this up could potentially cause severe harm to the vehicle electrical system. (You could brick your vehicle.)

Additional thoughts:

Fundamentally, I think this could work, but I haven't tried it...yet.
CANBUS is a HUGE potential monkey wrench.
This requires that one knows the basics of how vehicle electrical wiring works.
Having access to the vehicle shop manuals, especially for its electrical systems is practically a requirement.
This is not a step-by-step guide to be used by anybody not already comfortable working on vehicle electrical systems, and is in no way an encouragement to try this. I intended this to be more of a proof of concept post.
Doing any of this is entirely at your own risk, and I personally bear no responsibility if you try, and things go sideways.

Please comment, even if it's to say that this is nuts (but please tell me why), because I know that this is thinking waaaaay outside the box.
 

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Sounds like it would work. i looked through fuse diagram and couldn't find anything labeled close to homelink. I'll keep looking.
Yeah. I looked at the owner's manual entry for the cockpit fuse panel and didn't see anything suggesting Homelink. It might require looking at the schematics in the shop manual electrical volume. I don't have a set...yet.
 
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