sccs

Hi so I bought this car with a blown oem sub and decided to buy an aftermarket sub and amp after hearing about the complications about installing an 8" 2ohm sub without using the bracket.

So after pulling the aftermarket head unit (Sony cdx-gt540ui) I found this.



From further research on here it seems like the last owner had the metra harness done to the car.
Now with the aftermarket amp I need to use the rear rca output and with the metra kit it's already plugged in the spot. There's 3 sets but one is for sub and I can't use an external amp for that one.




I have no use for the oem sub but I would like to have the rear speakers working along with my subwoofer. What is the best way to handle this?

I was thinking of wiring them one by one straight to the head unit but from the looks of it the metra harness only uses 2 wires for both sides of the rear speakers, how is that even possible? I can't figure out which wire I need to connect to.
I've been stuck on this all day.