07 Nav Upgrade install issues

Sup everyone.  I'm new to this so bare with me.  I purchased a black 07 Avalanche LS without Bose and Navigation.  I upgraded my stock radio for the nav unit #15882767.  I purchased the unit on Ebay for $750.00 Brand New and it works great but after the install my speakers are playing very low.  When I raise the volume, it only goes to a certain volume.  The dealer installed it and flashed the unit twice but there's no difference.  The dealer said that he's gonna check with GM to see if I can get a Bose Amp and get back with me.  Does anyone have this issue when upgrading their stock radio.  Can I just get another amp in replace of the factory amp to amplify my volume and also my OnStar voice promp is very low, is this all a part of the same issue?  Anyone please help...... 

the navi unit is ment for bose speakers... the navi unit puts out either a high signal or a low signal to the speakers... meaning you will have to bypass the factory amp... or get a special wiring harness... im not sure if you understand what im saying... if not message back and ill explain more...

Ok.  I understand about the amp but what's the wiring harness and which do you prefer?  Everything works except for that.

I am unsure about what you will need.... heres a link http://www.jpcustoms.com/store/customer/home.php?cat=307 to a company who sells GM parts and has experience with what problems you are having... i would try giving them a call and telling them your problem... those are some of the AMP interfaces or wiring harness... i dont see one for adding a navi to a non-bose system... also when i had my 2004 Tahoe and wanted to retain the Bose-Speaker system but add a new head unit, the audio shop that i had all my work done at was able to by-pass the factory amp to work with an aftermarket stereo... something simillar may have to be done for your system to work...

Good looking out

No problem... let me know how it goes... i have a 2007 LT avalanche w/bose but no navi and want to upgrade sooner or later...

quote:

ORIGINAL: jazzson007

Ok.  I understand about the amp but what's the wiring harness and which do you prefer?  Everything works except for that.

 
all You have to do, is to buy and install any aftermarket 4 channel amplifier and buy non XM IPOD harness from American international ($15) and do a little modification to it. and then Your system will sound as good or better then factory BOSE set up

What would the non XM IPOD harness do?  What do you mean by modify it?

quote:

ORIGINAL: jazzson007

What would the non XM IPOD harness do?  What do you mean by modify it?

 
modifying that harness You can seamlessly integrate plug and play solution to add  ahtermarket amp to your Nav Radio

Any schematics on how this can be done?