AUX wiring to a Factory Headunit

[2rz-fte]

back story:
my wife used to have a 2009 yaris S sadan AT with ipod connectivity. Great car but i eventually swapped the head to a pioneer unit with BT capability. move up about 6 months or so i put that head unit in my tacoma daily driver/beater. pics attached.

i need some assistance on the wiring of the AUX input to the factory headunit.

i have done some research but its kinda confusing with the different model cars (liftback vs sedan)and such.

if someone could point me in the right direction thatd be great. ideally, i could purchase the a harness that plugs into the head and has the factory AUX input panel. thats probably not gonna happen but i need to know which wires are what so i can get the plug (on the head unit side) then solder my own 3.5mm jack.

thanks in advance for the help.

[2rz-fte]

is this the ticket?
http://www.yarisworld.com/forums/showthread.php?t=9852

i need to purchase a male 20pin connector and a factory AUX adapter?

[CTScott]

The jack next to the two blue connectors is the AUX jack.

On that jack 15, 16, 17 am 19 are used for the AUX jack

15 - ALI (left)
16 - ARI (right)
17 - ASGN (signal ground)
19 - AUXI (Switch input from OEM jack to enable AUX)

Looking at the back of the radio with the radio positioned as in your second picture, on the bottom row from the left the pins go - 20, 19, 18, 17, 16 ....

[2rz-fte]

So it seems that I need to pick up a 20 pin connector and wire it up. But I've read that the impedance across the contacts is very specific. If I wire a standard 3.5mm then I'll have to use a 2k ohm resistor but if I use a stock aux jack then I'll be fine.

Can I use any Toyota or scion jack?

[CTScott]

Originally Posted by 2rz-fte

So it seems that I need to pick up a 20 pin connector and wire it up. But I've read that the impedance across the contacts is very specific. If I wire a standard 3.5mm then I'll have to use a 2k ohm resistor but if I use a stock aux jack then I'll be fine.

Can I use any Toyota or scion jack?

Either the Toyota or Scion Jack will work. You would need the resistor on the switched leg if you wired it up yourself, but the OEM jack has the resistor built in.