I'm going to explain to you how you may easily follow these steps to go from a stock radio to one that will blow your ears out with loud thumping bass. Step 1: Notice the cover around the "radio head unit" These covers will simply pop right off when pulled on. So pop it off!
Step 1: Removing the "Head Unit" Radio
Depending on what brand radio you have this step will require you to use different tools. Now don't worry because they are all very similar and the concept is that of the same. You will need two "radio Keys" if you don't have them no worries go to local car audio store and they will give you some.. You will insert one key in the slot to the right of the radio as shown in picture and one in the left slot.
Step 2: Remote Wire
So now that the Radio has been pulled out of the dash we need to tap into this with another Cable that will run from this Remote wire back to your amp. This is what tells the amp to turn on and off when the radio turns on and off.
Step 3: Connecting the RCA's to Radio
Now the RCA cables are what carry the signal to the amp so the amp knows what frequencies to put out to the subs. The back of your radio will have two holes as seen here one red (left) one white (right) Insert your red RCA end into the red hole and the black RCA end into the white hole. This RCA cable will run to the input RCA connection to your amp as seen in the next slide.
Step 4: Connected the RCA's to Amp
Now this is just like the previous step in that the red end of the RCA's goes in the red hole and the black in the white hole. Now the only important part to this is that you insert them into the LINE INPUT. not the line out.
Step 5: Hooking Up the AMP
Alright now we need to hook the AMP itself up. We will need to connect a power cable, the Remote cable that we connected earlier to the Radio and a ground cable.
Step 6: Power to the AMP
Alright so we have connected the Remote turn on wire to the REM input on the Amp, We have ran the Power cable from the battery to The Power input, and now you need to connect the Ground wire from the Ground input on the amp to a Ground piece of your car. "Somewhere on your car that doesn't conduct a current" Like a bolt the holds down your seat or something like that.
Step 7: Connecting the Subs
Now take your subs that you are installing. "in this case two 12" Kickers" an look at the back of the sub box and find the connections. There will most likely be a "red" positive slot and a "black" negative slot. You need to take speaker wire and insert the positive to the positive and the negitive to the negative. We will then run this speaker back to the amp which will power these subs.
Step 8: Connecting the Subs
Now connect the + to the + on the amp and the - to the - as shown below. Now you have just upgraded your car stereo. Of coarse you need to slide your head unit back into the original slot and decide where you want to put your amp and subs. So hopefully this helped have fun.