onstar trailblazer

  1. sizzl3r

    Installing a deck into a car with ONSTAR

    I'm gonna be helping my friend install a system in his 2003 Trailblazer. I've done installs before but he has onstar, and I've heard it can be a pain to bypass... I'd like to keep all the chimes ect in the car. He said if Onstar doesn't work, that's fine. Do I have to buy a special harness or...