01 Tahoe went to put an aftermarket head unit in and found an extra plug that goes into he back of the factory stereo. when I hooked up the aftermarket head unit every thing works but there is no sound, so reinstalled the factory stereo minus the mystery plug and same thing no sound. it does not have a factory bose system just the onstar, I called the local car audio store and they said I need another harness to hook it up.

I don't use the onstar and never plan to, is there any way around this extra $120 harness expence

 

you can also bypass the bose amp .... its in the center console ...


unless you want to retain it ... in that case you need a retention harness ...

PAC,metra,ADS .... those are a few companies that have them

 

thanks for the input I dug into it deeper the other day and realized it had nothing to do with the onstar, thanks for the input