Originally Posted by hwarnxk
How hard is it to hook up an amp to my stock 6 disc cd changer for an 04 wrx and what do i need to do this?
Not hard at all. You'll need:
- A reverse harness to plug into your stock HU. It needs to have all 14 wires so that the illumination continues to work. See my homepage link. You'll connect two or all four of the speaker outputs to item #2 or 3...
- Line Output Converter (LOC) — converts speaker-level to line-level (RCA plugs). If your amp has speaker-level inputs, you won't need this.
- A wiring adaptor ("forward" harness) to connect to the car's stock radio harness. Again, it must have all 14 wires. Connect the ground, power, illumination, and antenna-remote wires straight through to the reverse harness (item #1). If you're sending only 2 speaker outputs to the amp, connect the other two across from the reverse harness to the forward harness.
Basically, items 1 and 4 will resemble a short extension cord, where you can connect after-market stuff in between. Since you did not cut any factory wiring, you can easily unplug all the new stuff and go back to stock.
People who install an amp usually run new speaker wires, but some opt to re-use the car's stock speaker wiring to avoid fishing through the door jams. If you do re-use the car's wiring, you can connect the outputs of the amp to the speaker wires on the forward harness. Otherwise, insulate the ends with electrical tape or heat shrink tubing.