Okay so I pulled out the stock 6 disk in-dash CD player and am hooking up a Pioneer AVIC-N1 navigation unit. I bought a wiring harness and hooked up all the speaker wires and everything just like i've done plenty of times before in other cars. Once plugged in and turned on the unit works just fine...except that no sound comes out of the speakers! This is bugging me because I took a seperate speaker and touched the speaker wire to each of the connections for all the different speakers in the car and for each connection that speaker worked just fine. That means that the problem is not from my connections, but somewhere behind the freaking dash in the wiring. And when I hook back up the original deck it just plainly does not power on. Is it something to do with the security system??? cuz that seems to be freaking out too.....

someone please let me know if you can help...

You have to bypass your onboard amplifier for your aftermarket head unit to function. www.crutchfield.com sells the cable . I think mine was about 8 $. that will solve your problem. basically the circuit is not complete regardless of how you wired the head unit. It like this with that stock head unit you have also the same on maxximas and my altima I owned.

Thanks man I discovered that there was an onboard amplifier and thought that might be the problem that it wasnt' powering on. Thanks for the help...