[Devilz311]

Which side of the seat? The Bose amp is mounted under the Right rear panel, in the cargo area... Maybe you're referring to the rear fuse block?

 

[Devilz311]

My vehicle did NOT come with OnStar from the factory, but the wiring is still there, and there is a green plug under the passenger seat, ready to be plugged into the OnStar module.

I believe GM built all TBs as OnStar-capable from a wiring standpoint, although not all got the module.

so that's what that plug is for... :duh: