[uro1]

From a technical standpoint they tell you the truth. The GPS needs to know if it is on the southern or northern half of the earth.
What I can not tell you how much work it is to get the car to recognise where it is.
Our mobiles for example use information from other sources. Like the net they are locked into or wifi hotspots with known positions. For ships and planes it is easy as the gps is working when switching over but your car would be likely off and shielded in a ship. It is possible the car does not use external source information and then a reprogramming might be necessary.