I'm replacing my windshield fairly soon, as well as my rearview mirror. i know that a lot of Jags have a compass in the rearview, but I don't know whether a mirror with a compass will work in a car that didn't come with it. Is the compass itself located within the mirror assembly, or is it behind the grille?

I would like to install a mirror with a compass, I just don't know if the mirror gets the compass reading from within, or from some external sensor.

Any knowledge would help, thanks