[Jacob dieleman]

I have been looking for hours online to find a diagram that is the same for my 2010 mazda 3, I need to figure out what wires are for the rear speakers.

 

[theblooms]

Just get a PAC AOEM-MAZ2 interface harness. Then not only do you not have to guess, you don't need to cut into any wires at all, either. It's a straight plug and play t-harness that gives you RCA outputs.

 

[Davids3]

If you don't have an amplifier (except for the head unit) why not just see what color the wires are at the speakers and back trace those to the head unit?

 

[Akmnhg5A]

This might be useful:

https://www.scosche.com/media/guides/ma531.pdf