I just bought a T1809 stereo to put into my 2004 4runner. Currently i am running a scion t1801 and a using a PIE adapter to run my mp3 player via CD changer mode. I know the newer stereo has an AUX input, but the mini jack is installed in the car, not directly on the HU.

My question is where can i get the wiring for the AUX plug? Does anyone have more information about how this is run to the back of the head unit?