I see, the radio, cd player, sat-nav, clock, tv and even the speaker settings shouldn't be a problem, but with the air con. and heater that will be.
What are your idea's on this...
http://www.lextasy.com/nav_converter_1160_prd1.htm
Also some models of the harrier have Automatic Air Conditioning, other have just normal-which i assume you would control on some sort of button on the dash.
Also I'm talking about the newer model(2003>)