’01 Highlander, add headphones?

 ****MODS*** Please remove my post in the car audio section....THANKS....(Seems this newb can't read forum instructions!!)

Hi all and thanks for a great forum!

I am hoping to add a headphone jack to our Highlander.  We have the upgraded OEM JBL 6-CD changer system with the separate amp behind the rear seat area.   I want to mount the jack within a couple of feet of the head unit, so I'm hoping that I won't have to run wiring too far away from it (HU).

So, do I tap into the harness that is coming out from the headunit (thereby bypassing the amp), or do I have to tap into the harness coming out of the amp (in the rear) to the speakers?  Either way, can anyone give me the colors or pin locations of the corresponding wires for the FL and FR speakers, from the HU =>amp and amp=>speakers? (I'll adjust the fade to full front when using the headphones). 

I was able to pull out the head unit and noticed that is has what appears to be a 20 pin connector on the harness, though not all of the positions are used.  My colorblindness tends to get me confused between blues/purples and reds/greens, so any postion info would especially be helpful. 

Thanks all for the replies/help.

Aw.....c'mon guys....

All I need is the pin position/wire color info for the 20-pin connector on the back of the JBL head unit (Toyota/Matsush*ta model no.  86120-48130, ref. no. CQ-ET8060A).  

 Thanks.....