The first step in installing a new after-market stereo in your Chevrolet Trailblazer is to remove the factory stereo. There’s no need to pay a car audio specialist to remove the stereo, as the process is straightforward and can be done in no time. Once the old stereo is removed, you can install a new stereo yourself, or take to someone else to have the new stereo installed. Make sure you have a socket wrench and socket set before proceeding.
Items you will need: Phillips screwdriver, Socket wrench with a 7mm socket
Open your hood and disconnect the negative battery cable from the battery. Loosen the nut holding the cable in place and slide it off of the battery terminal.