The Yuppie Button page talks about making lots of light. Now I needed to do the opposite, by "going dark" -- to vanish completely from Hyundai's data network, and avoid having the car being tracked or actively interfered with outside of my control. See, this is one of the showstopping problems I have with Tesla -- they *insist* that you have your car online all the time, talking to Tesla's cloud and sending telematic data. Thank you, NO. The range of things that Hyundai's BlueLink setup is able to do remotely to someone's car given only a VIN is totally scary. Not only did I want no parts of that, we all have every right to not participate in that nonsense if we so choose. As a first step I refused to let the dealer sign me for BlueLink, telling them that I could handle signup later myself if I wanted to. But I knew there was more to it, since the car as it came was still able to make a cellular data connection and send information about itself. The obvious question was to find and disable the cellular communication facility, or "telematics unit" as it is implemented in many vehicles.