[granger]

Take a look at this pic. The "AUX" button looks like a slider. Maybe this slides open to reveal a AUX input for the radio

 

[dmoore]

looks like Auxiliary Power to me...I think it relates to the covered power plug above the button. Also, its not with the radio but among other controls.

 

[granger]

check out the top row, far rightbutton on the radio

 

[YB2ND]

That is the ipod MP3 jack cover. It is the same as the cover in the 2006 Sienna

 

[Percy]

That will so rock! Pod support from the factory - nearly as important as good gas mileage. Nothing in the world quite like commercial free, hand-picked tunes while you're blazing a new trail somewhere!