ram infinity help

Is there a way to install a aftermarket head unit (kenwood 715dvd) without bypassing the factory amp.  The amp is buried in the dash somewhere and I can't figure out how to find it.  I did a search but there is no light green wire in my factory harness.  The stock radio itself has 2 plugs but my truck only has one harness going to the radio

the fact. amp is behind the glove box. you can pull the glove box out and access it from there. That is the only way I would do it. You COULD hook up the amp turn on wire (blue wire from aftermarket harness, usually blue on aftermarket HU). That sometimes will integrate the fact amp into the system. I have seen this fry out the fact amp and blow many speakers in the past, so be careful.