Ok I have a 06 FX4 Screw that did not come with the AUX input on the dash. I have the tray with the AUX plug but need to know what I have to do in order to hook it up to the stock HU. Its the 6 disc changer if that helps at all.

I have access to my buddies truck that I got the AUX tray from. Is the wiring harness that plugs into the port a seperate harness or does it tie in somewhere?

 

You either have to switch to a 07-08 head unit, or get something like the PIE FRD04-AUX to hook it up. The 04-06 heads are not programmed to accept the line in.

 

Ok. Gonna go check my friends house to see if he still has his stock HU. He has a 08.

 

Well I need to find a 07/08 HU with factory sub hook up. This sucks I thought it would be simple and free.

 

FYI, the sub hook up means it's an "Audiophile" option head unit, may help when looking for one.