Originally Posted by UCrewX5

You can add Aux input to a vehicle with nav as long as the radio module is from a 2003 or newer.

I retrofitted AUX into my 2001 by swapping in a radio module from a 2003 and it works great. The 2002 model year is easier to do because it already has the harness with the flat pin connectors. The 2000 and 2001 will require, in addition to an updated radio module, adaptor harnesses to convert the round pin connector style to the flat pin connector style.