It's actually even more simple then that, the anti theft devices I have looked at all work pretty similar, they are small and can be well hidden (that's their only real protection against disabling them) and are tied into the vehicle CAN bus where they prevent starting, shifting into gear or whatever unless their means of authentication is present. That is usually a button sequence, a RF/bluetooth keyfob or just your bluetooth phone.
These things are not bonded/mated/authenticated to the vehicle(engine/security ecu), if they would be they could be removed but the vehicle would not start.
The manufacturers actually could have implemented an infrastructure (authentication/encryption) in which news keys and ECU's can not be easily programmed to the vehicle (CAN-Access) decades ago but they want to keep selling new cars for the stolen ones. In the case of our TRX's they rip out the light switch because that seems to be the easiest access to the CAN behind the security gateway which just acts as a filter.
Ravelco seems even more simple then Bells first telephone, it just looks like a bunch of wildly crossed wires, maybe some resistors and crossconnections thrown in. Nothing any good electronics guy cannot figure out with a voltmeter given the time, think there's even a Video out there of that.
So I personally don't get the hype about the devices on here, they are only a first line of defense, after that you need tracking and you need to take action yourself.
If I find this in your car/truck I would just cut it out wire by wire and start programming the new key (which I don't know how to do btw)
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To answer more clearly, the CAN access is only needed for programming a new key, this thing right here can be manually found in the wire loom and cut out...