Done aftermarket swap before, but adding a PAC steering control adaptor just confuse the hell outta me. Would anyone mind explaining in brief how the harness from crutchfield gets connected to steering control n head unit ?

 

i installed Metra Axxess ASWC-1 in my 2006 tc. Works perfect.
beside tapping few wire into the harness, it is pretty easy,
Here is the instruction for my ASWC-1
http://contentdocs.installernet.com/...icle/10957.pdf

 

I would highly recommend the Metra Axxess piece over the PAC unit. I've had way too many instances of the PAC units loosing programming or just not being able to get them to work in the first place. Never had a problem with a Metra one once.