Connector wiring diagram for the car audio ISO connector.

Note that some of the pin´s may be missing in your car / connector. This is because your car does not provide the given function.
 

 
Function Pin Function
Speed dependent volume 1 Right rear speaker +
Muting control 2 Right rear speaker -
Reversing light switch 3 Right front speaker +
12V 4 Right front speaker -
Automatic aerial 5 Left front speaker +
Illumination 6 Left front speaker -
Ignition 7 Left rear speaker +
Ground 8 Left rear speaker -