The remote wire is run through the firewall behind the clutch pedal. Pull out the gasket/grommet and find a second grommet there. Pok a hole slightly upwards and push the wire through until it can be reached. It may be dificult due to the engine bay being cramped in this area. Just a warning.
Onto the most challenging part of the wiring: sending signal to the factory amp. Four RCA connector ends need to be purchased. They need to be soldered to each positive and negative speaker lead on the adaptor harness. Soldering them to wire and then soldering that wire to the leads is recomended. Plug the preouts into the back of the h/u. This picture should help, if it doesn't let me know and I will try to explain it better (Brown wire is the RCA's).
Essentially this will convert the preout signal to a line level signal, which is how the stock reciever communicated with the factory amp. The Pioneer system is designed to use a common wiring harness and thus both the speaker and the power antena leads are utilized to control it. I am under the impression that the stock reciever is sending a higher voltage to the amp through the speaker leads (12v most likely), but mine is sending a cleaner signal and I am thus able to turn it up louder w/o distortion than the stock setup.
A few suggestions
-Solder and heat shrink all of the harness to harness connections. Soldering provides a stronger signal transfer and higher durablity than any connector.
-Use twist connectors on the remote line out to the amps and ignition lead into the reciever. This will help if you ever have to pull the unit out. No wires will need to be cut.
Here is a shot of all the wires run. I have an extra remote and rca ran for another amp in there too. The black wire on the left comes from the ignition fuse and the blue on the right is the remote line to the non factory amp I plan on installing.
Lastly the h/u needs to be mounted in its adaptor plate and installed. Once again i picked mine up for a deal, $15 at a local place. I had to use the spacer, the cobalt does not have much mounting depth for h/u's. Something to be aware of. Mine turned out fine, but thats it. My cables all got in the way and made it dificult to get it all the way in. But it is there now. Use the original four screws to mount the new plate and assemble all the trim pieces in the oppisate order.
Here are some finished shots.
Using the Alpine deck I have been able to increase the output of both the components and my sub without distortion. I'm certain I could achieve higher SPL numbers than the stock h/u, not neccesarily huge but better. The sub is able to go louder with less distortion.
Now some interesting things I found.
I pulled the factory amp out just to look at it and how it was controlled.
It is located the lower left of the steering wheel behind the drawer with the trunk release button.
I am reaching up for it here
Here are two shots of the bracket. First has the amp still installed and the second the amp is removed.
And the amp on the floor.
It was very difficult to remove. The amp is wedged against the dash and everything else really well and i tore up the surface of the insulation pulling it out. I think it was worth it to take a look, but now you all can see, so don't do it
haha. I will also note that the rear speakers read as 2 ohm. If the amps output is 270W at 4 ohm we are getting double the power claimed publically. 270W always seemed too little to be running all those components especially now that I can turn it up.
Another cool thing I found under the dash was the electronic steering controller and mechanism. Its nice to know where that is. I just think it was a cool find.
Lastly here is my trunk. I will let you guess what is going to happen.
More photos can be found here
Amy comments, corrections, questions, or criticisms are welcome. If I get good feedback I can make this how to easier to read and understand.