Not sure if this will help anyone, but who knows. I had a Saturn SL2 (sucked lol) and had a system in there. Well, totaled that, sold my headunit, and kept my amp and subs. I was thinking, there had to be a way to put subs on my stock system. Well, with the help of my brother and $25 I did it. No pictures because I don't feel like ripping apart my back seat and panels again, so I'll explain this as best as possible.
The part you need is a Line Output Converter (LOC)
http://www.crutchfield.com/S-QuO8Jv...?g=721&I=101PL2
I bought mine at bestbuy for $24.99
Basically it is a small box that has 4-6 wires coming out, 2 white (one has black stripe), 2 grey (one black stripe), then 2 brown (one black stripe). The white and grey ones will wire into the rear speakers.
You DO NOT have to splice them before the amp if you have the infinity system. I did not and everything works fine. Your amp will only amplify the signal up to the ampage it handles, not over amplify the subs, while the back speakers will still recieve the amplification that they did before.
White splices into the left yellow w/blue wire
White w/black splices into the left gray w/blue wire
Grey splices into the right yellow w/red wire
Grey w/black splices into the right greyw/red wire
Browns aren't used.
Then, when those are wired up, you take your RCA cables and plug them into the LOC, then run those to your amp. Plug them in.
Alright, wire your amp up to your subs as they would normally. I found the best ground is right under the spare tire, back right. I had a screw already there, just sanded the paint down and rust on the screw, then hooked it up! Now, you need to get a way to turn on the amp w/the remote wire. Just find something that turns on with the car. My brother took a test light and found a blue wire in the back left that turns on. It was near the speaker, in a white box. Just stick the test light needle into the different box holes, while grounded, and the car on. If the light turns on, turn off the car. If the light turns off, splice into that wire. The remote wire will be spliced into that wire, then run to your amp. This will turn on your amp whenever you turn your car on (which is when you want your amp on, or else it will drain your battery!)
To set the gain, put the gain to nothing, set the volume to what you normally listen to your radio at, then turn the gain up until it distorts or you have enough bass (is that possible??). Set the freq and crossover so that your subs play just the bass and hit hard.
Enjoy your thumping!
