T1808 head unit HELP!

[jibberjabber]

Hi, feeling like a big idiot right now, but I've been searching everywhere for the info with no luck. Can any of you point out the sub port on the back of the head unit. Also trying to install a sub with an amp. Is there any way to convert the rca cables to fit to the stock port? Appreciate the help!

not sure of how to post pics so here's a link to somebody's unit which is the same as mine...

Scion T1808 w/ Direct ipod connect cable - TTORA Forum

 

[jibberjabber]

So after a sleepless night of research and being completely new at this... I stumbled upon what I think might be the answer.

From what I've found, would the best approach be to add a line output converter to my system by splicing it with the front speakers? This way I could run my rca cables to the amp which will power the sub.

Can anyone familiar with this stuff confirm my theory? Also if its correct would I only need a 2 channel converter since its only going to be linked to my sub? (basically only using one of the channels)

 

[jibberjabber]

So I'm pretty sure my guess is correct... can anyone tell me which wire in the back that plugs into the head unit is my sub output wire? Also since I didn't have a jbl system to begin with would I have to add a wire since it didn't come with a sub to begin with?