Help installing radio

[amag490]

kind of new to the diy side of owning a car. i've already installed speakers in my car, that was pretty easy for me. however, i have a new pioneer stereo that i would like to install as well. it is pretty straight forward, got the install kit and wire harness. the only thing that is confusing me is when i took the factory radio out, there seems to be an extra plug (that was plugged into the back of the factory radio) that i just dont have anywhere to plug into the adapter/wiring harness or new stereo. i've attached pictures. any help would be great. would like to do this myself.

im holding the plug that i don't know what to do with.

wire adapter/harness

another shot of the adapter

 

[IAExpy]

images are real small, can you post higher res, may make helping a little easier

 

[Shadowless127]

It's one of the following

Rear audio controls
Sub/amp plug (Only if you have audiophile system w/ 6CD changer head unit)

 

[amag490]

It's one of the following

Rear audio controls
Sub/amp plug (Only if you have audiophile system w/ 6CD changer head unit)

well i do have a sub, rear audio controls make sense. so i just wont have those controls working if i dont plug it in? fine by me.

 

[Shadowless127]

well i do have a sub, rear audio controls make sense. so i just wont have those controls working if i dont plug it in? fine by me.

Do you have the factory sub/amp?

 

[amag490]

Do you have the factory sub/amp?

after market

 

[Shadowless127]

after market

then I'm 99% sure that plug is used for the rear audio controls.

 

[GAINMOB]

i believe so too...mine is the same way and i just left them in there with no worries...so my rear controls dont work either...dont want them too...dont need anyone changing my stations or source...but i do need to get my steering control done

 

[VexedEX]

Mine aren't hooked up either... You don't need it to be... Just left mine sitting there. As long as you radio is working you should be fine.