I have a new Z2 that I am going to install in a 06 Trailblazer SS that had a bose system in it.

I have a 5 channel amp that will be running 4 door speakers and sub. So I will be using the stock Bose amp and the stock dash speakers for Onstar and chimes.

The PAC instructions show 4 channels of hi level wiring coming from the radio to the PAC unit. I cant imagine why I would use these but did not notice anywhere where they were optional based on configuration.

So the question is, are they required for some reason I cant think of?

I think they are for the onstar and built in phone. I have an 07 tahoe and had to buy an adapter to get the onstar and phone to ork with my z-1. The adapter has a volume control on it and I hap to take it back to the shop because they didnt have it loud enough. Now its too loud. I would let a profesional install it since it has the onstar.

Are you upgrading the door speakers or adding them?

If not, just use the Bose amp to power them...I'm 90% positive that any aftermarket amp hooked up to the factory Bose speakers will sound like garbage...Buy the PAC adapter(forget model) that will retain factory chimes and Onstar....and just hook up your sub to the aftermarket amp.

I have an 03 Silverado SS, and the factory stuff sounds great, especailly once you add an aftermarket sub(I have 2xJL12w6). You then can tune out the bass to the Bose system and get much more clarity out of them.

If you are upgrading the door speakers or adding some, then you are on the right track..And you need to use those wires going to the PAC to retain the chimes. Personally, I would find the adapter to get rid of the chimes. I originally wanted to keep my chimes, but accidentally baught the wrong adapter....Now I'm loving not having the chimes...I kinda miss the warning chiimes, like low fuel....but there is a big dummy light in the cluster...Another problem with retaining th chime, is that you will not be able to adjust the volume without the stock head unit...I believe you can set it to low, before you pull the stocker out, and it should still be set on low, when you finish your install...If yours is anything like mine...low is not very low....

I installed JL Audio speakers in the doors. Components in front and straight coax in back. I have it working now minus a couple bugs. I have the Os-2 bose connected to the bose amp and the only speakers on the bose amp now is the jash. They are just for onstar and not audio.

I was able to remove all the speaker wires in the pac harness on the input side.