So recently I got a new single din stereo for my truck because it now has iPod hookup etc. etc. Before I got it the old deck was screwed so I pulled it out and noticed there were 2 wire clusters that plugged in. When I went to get a wiring harness they only gave me the one in the first picture and said I need nothing else.



I was a little ticked because I knew there was another plug in there and pretended like it didn't exist. My sound is decent but not great. Weeks later I find this



So I know there is something that plugs into the second wire. So WHAT does it do.

 

I'm no expert, but I am guessing that second plug is for a sub or amp, that you may not have, so you wouldn't probably need it.

 

no, that second plug is not needed. The radio probably has 2 plgs on the back the big wiring harness an the other smaller one. You dont need that, its just for other trucks that dont have that type of wiring harness

 

The second plug is for the factory subwoofer. It plugs into the plug on the harness and then you plug the rca into the back of the stereo. The blue wires with a white stripe need to be wired to the blue/white wire coming from the back of the head unit.