Disconnect the cable from the negative battery terminal. Remove the center bezel panel from the dash. Remove the screws and pull the radio out of the dash. The four screws secure the radio and, if equipped, the CD. Disconnect the antenna lead and the electrical connectors and remove the radio. Installation is the reverse of removal. For the door speaker, remove the door trim panel. Remove the speaker retaining screws. Unplug the electrical connector and remove the speaker. Installation is the reverse of removal. For the rear speaker in Xterra/Pathfinder, remove the rear quarter panel trim. Remove the rear speaker mounting screws, unplug the electrical connector and remove the speaker. Installation is the reverse of removal.