I went and bought a jensen vm9312 deck off a friend for 150 bucks. Now i already have 2 12' inch jl subs and a 900w amp already hooked up to my stock stereo. What do i have to do for the new deck to be installed. I know i need a new harness and a plastic piece to make the new deck fit. I was also told i need new audio cables to go from the amp to the deck is this true?

 

If you are using RCA cables from the stock headunit to the amp, then you should just be able to unplug them from the stock headunit and plug them back into the new stereo. You will need an adapter harness for your car as well. You will not need to attach the speaker wires from the headunit to the adapter, just cover the ends with electrical tape. The only one wires from the headunit you need to attach to the wiring adapter are the constant power, aux power, dimmer and ground. The amp turn on lead will just need run back to the amp, not wired to the adapter. Then like you said you will need an installation kit so the headunit will fit in your dash.

 

see with my rca cables the one runing from the amp are actually running to a box that is installed right by my rear deck speakers. Im not sure how it works its just spliced i think into my rear deck speakers and runs like that but im not 100% sure. I can get a picture to tell you what im talkin about if needed

 

Hmm sounds like you have a factory amp powering your speakers. Disregard my last post, it really doesnt apply. I misread your first post. Im not sure I can help you because I am not familiar with how the factory amp is integrated into your stock system. Maybe someone who has a car similar to yours could be of more help. Sorry, good luck.

 

no i have an american bass amp hooked up and still have the stock amp. There is just rca cables running from my aftermarket amp to a black box that was installed

 

you shouldnt need wires from the stock amp, stock amp will be literally obsolete if your using aftermarket, and you run remote and rcas from deck to amp, and then just run power wires to amp, from amp run the speaker wires, you can sell the stock amp or take it out or whatever now