The key fobs transmit a digital code that the onboard computer reads. the code is never the same twice in a row and changes according to a pseudo random scheme that is synched between the onboard computer and the fobs. Further, a large number of different pseudo random algorithms are used, so that if by chance one fob syncs with the wrong vehicle one time it won't do it a second time. Anything breaking that has either insider information or an extremely sophisticated computer program. I'd bet on insider information from someplace like onstar. Further a rheostat is just a variable resistor. Who would that change a transmitter frequency?
“Further, a large number of different pseudo random algorithms are used, so that if by chance one fob syncs with the wrong vehicle one time it won’t do it a second time. “
Just got back from a business trip in Tampa. At the hotel, after checking out at 5am, we used the key fob to unlock the rental car. Our car, AND the car next to us bot unlocked, and they were different models.
We did it 5 times in a row because it freaked us out. It was still dark, and the tail lights of the car next to us came on, which surprised us. We did it again, thinking someone else was doing it or someone was in that car. Nope. Just us.
We knew it should be impossible, but there you go.