I've got an '08 Sport model and my Auxillary jack just stopped working.

Used to plug in my (droid) phone and play my music from it - process: plug in... Aux lights up on screen - play music.
Now? plug in... nothing happens.
Press the Aux button on the dial - nothing. no screen change, no music.

Where do I find a wiring diagram... perhaps I've got a wiring issue?
Help.

 

I doubt you'll be able to get a schematic of the internals of the radio. However, that's most likely not at all necessary to repair the problem.

My guess would be the jack itself or the solder connections that attach it to the circuit board. It sounds as though the radio isn't properly detecting that a plug is inserted, which it presumably knows from some of the "extra" contacts in the jack, such as would be used on a boom box to cut out the speakers when a pair of headphones is plugged in.

You might be able to get it working again by squirting some canned air or electrical contact cleaner in the jack, in case it's just a matter of the contacts getting gunked up a bit. (Don't use WD-40 for this; it's not an electrical contact cleaner, and will attract more crud as time goes on.)

 

Just a stab in the dark if you are talking about the Aux (USB type plug) you need to cycle (3) through the Aux input button..... AUX, CD/Disc, USB (ipod) by repeatedly pressing from the dash (not the wheel column). Also turn the volume up a bit on each setting as I think they are independent. I have a DAB (digital audio Broadcast) portable plugged into aux (3.5mm jack input) and an iphone plugged into USB port but need to press aux to switch from 1 external input to the next. You may have pressed aux twice and changed it from USB to 3.5mm jack input where you have nothing connected at the moment.