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4G Modem Disabling Instructions:

drummerboy

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I know there are at least a few of you that share my concerns for many various reasons:

Weird Insurance situation - if anyone can exp
Disabling 4G modem on 2019+ cars
Looks like the Norks are trying to hack into my car

Whether it's data collection, raised insurance premiums after a track day, hacking and cyber attacks, or some other concern, we shouldn't be forced to have our cars sharing who knows what with who knows who. Our cars have a telematics control unit (TCU) that does... well, I can't say for sure what it does other than that it has something to do with the 4G modem communication and data collection. https://en.wikipedia.org/wiki/Telematic_control_unit

I have a handy dandy RF meter that very simply shows me the strength of wireless RF radiation. I meant to do this a long time ago, but this afternoon I turned it on and took it to my 2019. When I opened the door, I heard the familiar chirps and buzzes of a mobile phone, but my phone was far away, inside the house. With all of the radios turned off (mobile data, bluetooth, etc.). And in airplane mode. My phone wouldn't have spiked my RF meter from the garage anyway, but I wanted to isolate any RF from my car for this experiment, so my Wi-Fi was also turned off. Prior to getting in my car my meter showed nearly no RF signal whatsoever (I live a decent distance from any significant broadcasters such as cell towers).

Awhile back I decided on a plan of attack to disable the TCU. The first trick up my sleeve? Pull a fuse.

And with that... I present to you the full detailed instructions on how to disable the 4G modem:


STEP 1) Disconnect fuse #10: Telematics

STEP 2) ...


There is no step 2. At least not for now (let me know how it goes for you).

Could it really be that easy? I know it's only a 5A fuse, but I had in my mind that perhaps navigation or bluetooth might no longer work, and I'd have to try plan B. But no, nav and BT are still fully functional. This little fuse appears to be for just the modem. I can still see the RF signal from the key fob and bluetooth, but the modem is gone.

Stay tuned for episode 2 where I reconnect the fuse and triangulate the RF signal to the modem location for possible removal (sure, there might be a more conventional method for finding it, but this is more fun).

So, there you have it, fellow tinfoil hat conspiracy theorists. Very simple. Very effective.

If you find a potential problem such as something else not working as expected, let me know and I'll expedite the modem location process for a try at just unplugging it.

Epilogue:

Very many of us have no use for our cars sending data to someone. I get in my car to go from point A to point B for whatever reason. I like horsepower, an ode to exhaust written by chewbacca himself, and good sounding tunes. None of these things require me to give up privacy. I don't even know what convenience the 4G modem gives me... in-car Wi-Fi? If I'd like in-car Wi-Fi then I'd have to consider my options. But since I have zero use for it, I've very happily disabled it. No need to give that data for free to whoever wants it. There's no need to just throw up your hands and say Corporation A knows this about me, Corporation B knows that about me, might as well just let Corporation C have this other data. What our phones do, what EZ Pass does, etc. are all separate issues that can be decided upon and handled separately from our cars sending whatever data they are sending.
 

Tomster

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Oh frikin A yea!

I'm going to link this over in the 500 section.
 

drummerboy

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rx5chc6.png


So, Tom found this photo diagram (Thanks, Tom!). He has ruined my fun by locating the TCU which appears to be somewhere in the trunk. Though I guess it's for the best, as I hadn't considered that my RF meter would certainly lead me to the antenna, which is apparently in the package tray area underneath the rear glass.

Item 5: TCU antenna
Item 6: TCU
Item 8: Cellular antenna splitter
Item 9: Cellular antenna


So, who wants to go digging first?
 

Tomster

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rx5chc6.png


So, Tom found this photo diagram (Thanks, Tom!). He has ruined my fun by locating the TCU which appears to be somewhere in the trunk. Though I guess it's for the best, as I hadn't considered that my RF meter would certainly lead me to the antenna, which is apparently in the package tray area underneath the rear glass.

Item 5: TCU antenna
Item 6: TCU
Item 8: Cellular antenna splitter
Item 9: Cellular antenna


So, who wants to go digging first?
Actually, it was @The Chairman who sent me the document. It saves a lot of digging around.

Whats the point if the fuse took care of it.

I do believe that document indicates the primary 4g comm antennas are located in each rear quarter panel. The shark fin antenna will also function as an antenna.
 

drummerboy

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Also, here's the passenger foot well diagram from the owner's manual:

CmxQSqr.png


Slot 10, tiny little 5A fuse, orange.
 

drummerboy

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Actually, it was @The Chairman who sent me the document. It saves a lot of digging around.

Whats the point if the fuse took care of it.

I do believe that document indicates the primary 4g comm antennas are located in each rear quarter panel. The shark fin antenna will also function as an antenna.
Agreed, what's the point if the fuse takes care of it. That said, just in case someone discovers some obscure thing that also might be tied into that fuse, the diagram is handy to locate the TCU to unplug it.

I found it interesting what the document you posted said about the antennas. I think the conclusions about disconnecting antennas from the TCU are incorrect, sure that might make it not work, but it's still broadcasting, albeit not very well. Also, sure, it uses the nav/GPS antenna, but not for data, only to know the location of the car. I wouldn't worry about the nav/GPS antenna at all in regards to the TCU, worst case scenario if disabling the fuse or the TCU itself poses some other problem we haven't thought of yet, then a guy could rip out the cellular antenna and cover the TCU in a faraday cloth and there's no way any data is getting in or out.
 

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drummerboy

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you win the prize, D. what a useful post. never even thought of this...
Thanks, dude. It's been on my list to do for a year, today I decided to finally try it out. It figures that it only took 5 minutes, eh?

Also, as is probably evident in my OP, I'm not a fan of sending out data willy nilly. I'll wager my GT350 that before too long it won't be possible to disable the data connection on a new car (imagine trying this on a Tesla). Access to this data would make insurance companies cream their collective pants.
 

motodad

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Thank you for this! I have been curious to do the same on my 2020 F350 PSD. I recently had an interesting experience where the dealer service manager was able to tell me a few accurate things about my truck when it was in my possession not on the dealer property... He told me he got the info on his computer from the Ford system tied to the Ford Connect infrastructure in the cloud.. I immediately disabled all the Ford Connect and Wifi options in settings but I want to make it impossible for my truck to phone home.

Is fuse #10 labeled specifically as telematics? I am going to research the same on for my PSD.
 

drummerboy

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Is fuse #10 labeled specifically as telematics? I am going to research the same on for my PSD.
When I started researching this, one of the first things I did was search the fuse section of the owner's manual for "modem" and "4G"

I did not find those anywhere, but this one sounded interesting:

uamKdfT.jpg


I wrote that down along with a few other suspect items, but when looking around at what they do, telematics turned out to be the winner.

I would imagine the fuse section in your manual will also show telematics, or at least lead you in the right direction. If all else fails, find a diagram like the one above showing the location of the TCU, grab that bastard and rip it out.
 

motodad

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I would imagine the fuse section in your manual will also show telematics, or at least lead you in the right direction. If all else fails, find a diagram like the one above showing the location of the TCU, grab that bastard and rip it out.
Thanks again. Can't be much more than the TCU if it is only a 5A fuse. Will pull my manual and test tomorrow morning!
 

drummerboy

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He told me he got the info on his computer from the Ford system tied to the Ford Connect infrastructure in the cloud.. I immediately disabled all the Ford Connect and Wifi options in settings but I want to make it impossible for my truck to phone home.
Also, I should state that turning these settings off does NOT stop your modem from sending the data out. Our tech toys like to give us a false sense of privacy and choice.

Thanks again. Can't be much more than the TCU if it is only a 5A fuse. Will pull my manual and test tomorrow morning!
Agreed, but you never know! That said, the fuse chart does say "Telematics." and nothing else. Score!
 

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