Ok, so last night I took out the factory HU and I noticed 4 plugs on the back of it. I know that one of them is the power, accessory, dimmer, etc.. plug and the other is the outs for the speakers. But what are the other 2? I figured that one of them was for the steering wheel controls but that leaves 1more....

Also where can I find the vehicle speed sensor wire agian?

 

The two remaining are the sat cable and the steering wheel controls.

 

when you say sat cable do you mean satellite radio? The car is not equipped with the option... will it still have the plug and will it still be plugged into the back of the radio?

 

Yes, I mean the sat tuner prewire cable. My non-prewired 03.5 sedan had a plug in there that I unplugged when I installed the sat tuner cable. I don't know what it did.