Does the AUX input come standard? I have 2005 TSX with Nav but can't find the AUX input.

 

No it's not.

AUX was introduced in 2006 Model.

 

There's no 3.5mm AUX in 2004-2005 TSX but there's a 14-pin connector underneath the Stereo. There are a lot of aftermarket kits that connect there and provide AUX/USB/BT/iPhone features.

Most common are GTA Car kits, GROM kits and there are more in $100-$120 range.

 

I have a GROM unit I would be willing to part ways with.