Stock Amp is 4 channels!
I'm a new Crossfire owner (just bought an '04, and am loving it), but one of the first things I wanted to do was fix up the stereo. So, I read a bunch of the threads here, and it seems like everyone believes the stock AMP is just a two channel unit. After I looked at the wiring (it's great that the service manuals are available here!), my thought was that the AMP had to be a 4 channel AMP, that they wired the front and rear channels together because the stock head unit was only two channels (no one I know designs an AMP w/ 2 inputs and 4 outputs...)
Anyhow, I tested my theory by going in and clipping the wires going to pins 6 and 7 on the AMP. Sure enough, the door speakers on the right went out, but the sub still worked. So here's the pin out I determined:
EDIT -----
AMP pin 6 - (was Right Door speaker input (+) ) should be Right Door speaker input (-)
AMP pin 7 - (was Right Door speaker input (-) ) should be Right Door speaker input (+)
EDIT-----
AMP pin 10 - Right Sub input (+)
AMP pin 9 - Right Sub input (-)
AMP pin 1 - Left Door input (+)
AMP pin 2 - Left Door input (-)
AMP pin 8 - Left Sub input (+)
AMP pin 3 - Left Sub input (-)
I installed a new head unit (a Pioneer DEH-P6100BT, highly recommended by the way). I used the existing wires to drive the Subwoofers from the sub preamp outputs, and ran two new pairs of wires between the door wires I clipped at the amp (pins 6/7 and 1/2) and the front speaker preamp outputs. Works like a champ, and you can individually adjust the volumes of the subs vs. the door speakers using the fader.
As a side benefit, if you do this, you can use the adjustable crossover functions in the head unit (almost all of them have them) to avoid having to put the capacitors in the doors. I set mine to limit the subs to < 125 Hz, and the front speakers to > 100 Hz. I'm very happy with the results.
Last edited by Spark; 09-10-2009 at 11:32 PM.