Okay, so just to clarify, you've wired your EQ/Amp up to your front and rear speakers, and had no problems in doing so, but now you're looking to find the wires that WOULD HAVE connected from the back of your headunit TO your speakers?
I'm just trying to understand your problem here. Like I said, without pictures, it's difficult to diagnose.
If the above is the case, you would simply wire the Amp/EQ in-line with your original speaker wires since like I said earlier, there are no RCA outputs on the stock headunit.
And also since you're amplifying the front AND rear speakers and it appears as if you only have two wires going FROM the headunit TO the Amp/EQ, you will have to splice/T-in the wires that go FROM the headunit TO the left and right wires on the Amp/EQ.
If you had a 4-channel amplifier, then you could wire each one individually, but from the information you're giving me, the amp you have only has two channels.
Here's a wiring diagram. I excluded speaker negatives for clarity, and used the colors you provided:
The wires you would have to T together (Where it says "Stock Speaker Outputs" in the diagram) would be from the headunit, Left Front-Left Rear and then Right Front-Right Rear which correspond with the following colors:
Left Front Speaker Positive Wire (+): Gray/Purple
Left Front Speaker Negative Wire (-): Gray/Yellow
Right Front Speaker Positive Wire (+): Dark Green/Purple
Right Front Speaker Negative Wire (-): Dark Green/Yellow
Left Rear Speaker Positive Wire (+): Dark Green/Tan
Left Rear Speaker Negative Wire (-): Dark Green/Gray
Right Rear Speaker Positive Wire (+): Dark Green/Brown
Right Rear Speaker Negative Wire (-): Yellow/Gray
Again, if this isn't what you're looking for, let me know, I'll PM you my email address and you can email me your pictures and then I'll have a much better idea as to what's going on. I'll also resize it and post it here so others know what's going on.
Edit: I also realize I have the ground wire connected to the headunit-- it was a simple, quick draft.. haha
