Originally Posted by Wavemandan
I have a 2007 Sti sedan and I have an aux port but I can't get the oem head unit to turn to it.
Most likely explanations:
A) Your STi originally had a different OEM HU (with aux capability --that feature was added in 2007 Impreza models), but the previous owner removed it for some reason and replaced it with an older model.
B) Yours is the one that originally came with your car, and someone used an aftermarket accessory to add aux. Could be an FM modulator (where you must tune to a certain FM station, and possibly need to flip a hidden switch to activate/deactivate), or a hack soldered inside the HU. Pull out your HU and see where the aux cable goes.
Is it a factory aux jack (where the ashtray would be)?
What is the model number printed on the front of your HU?