Where is the 2006 ford explorer aux input located?

On 2006 Ford Explorer models, the auxiliary input jack was still not standard equipment. Though it was featured on some higher trim levels (and a part of the tech package), just because Your head unit indicates an aux input doesn't mean You have one. It wasn't until 2011 that it became standard. Still, You may be equipped with one all the same -- if You are, You should be able to find it in the center console, on the wall that's nearest to the front of Your vehicle. If Your model isn't equipped, no worries; several aftermarket solutions still exist. You can pick up a head unit from a company like Pioneer, Alpine, Sony, JVC, Boss, etc. For as little as around $100 that includes an auxiliary port. It's a relatively simple upgrade that You could likely do in a long afternoon with the help of a few YouTube videos.