What wire do i tap off of for the Remote wire if im setting a system up using the stock Upgraded pioneer head unit in my 2008 scion tc. What color is the wire

 

for some reason there are way too many harnesses on the upgraded HU. i can't remember which one i tapped into, but it's a blue wire. check for the harness with a red, yellow, and black wire as well.

 

http://home.cfl.rr.com/icdedppl/faq.html#c12

This may or may not apply to the upgraded one, but I think it should

 

It's the orange one from the power harness. If you have an '08 and plan on putting the amp in/near the trunk you can tap the orange wire in the harness to the factory sub-box. There's no real advantage to this I guess; because you still need to run the RCA's to the amp so you just run the 'amp on' wire along with them.