Wiring Question Radio Side Harness 2007 Mazda 6 without Bose
 

I am building a T harness to wire in an amp into the factory wiring. I have a standard metra harness as well as a reverse harness so that I do not need to modify the factory wiring.

The reverse harness (into radio) has about 6 additional wires than the vehicle side harness.

I want to know what each represents on both the radio side and vehicle side so that I can add new pins to the standard harness.

I would say at a guess, the harness is used for more than just your exact model, so its pre wired with wires used on other models, not just your's.