Almost certainly via wiring into the CAN bus. There's quite a few aftermarket addons that require you to run a line to the internal CAN bus to have certain thin

Almost certainly via wiring into the CAN bus. There's quite a few aftermarket addons that require you to run a line to the internal CAN bus to have certain things function (like popping the trunk, for instance). I've also seen some Bluetooth based ones that require using your phone, which then relay to the Tesla app to perform functions. Not sure who's using those quite frankly, seems like a bad solution. Also this panel appears to do thing you cannot do in the Tesla app, so I don't think it's using that method.