I just grounded the proper wire on the deck I just installed(it was a kenwood) and it worked like a charm. It will probably be along the same lines for the factory nav unit . Sorry I couldnt answer your question 100%
i have a kenwood unit in my truck and thats what i did for it. on the factory unit you have to be in park with the parking brake on. so i dont know if there are two wires you need to ground or just the one.
i have a kenwood unit in my truck and thats what i did for it. on the factory unit you have to be in park with the parking brake on. so i dont know if there are two wires you need to ground or just the one.