what exactly is the purpose of this orange wire and where do u connect it??? to the orange wire in the vehicle harness??

what vehicle? and it depends on the manufacture of the harness you are using. in a metra harness there are 3 orange wires

orange is ilum (doenst dim with ip lights)
orange/white is dimmer positive (dims with ip lights)
orange/black is a negitive dimmer (special function most foriegn)

well i dont know what manufacture the harness is but its a 92 honda accord i only have 1 orange wire coming from the harness so i dont know if i conect that to the orange from the head unit let me know

that orange wire on your 92 accord is a ILLUMINATION wire.

hook this up to the illum wire on the avic...should be orange white i believe if my memory is correct.

let me know if im right