Disconnect the negative cable from the battery. For Highlander models from 2013 and earlier and Lexus models from 2009 and earlier, remove the center trim panel around the A/C Switch, or the trim panels around the shift lever leading to the A/C Switch for Lexus models. Once the trim is removed, the mounting fasteners will be exposed; 2003 and earlier Lexus models have two fasteners at the bottom of the A/C Switch and audio unit, while 2004 and later models have four. After removing the fasteners, detach the audio unit from the A/C Switch by removing the mounting bracket screws. Pull the assembly out slightly and disconnect all electrical connectors. For Highlander models, remove the mounting screws for the A/C Switch and audio unit. Installation is the reverse of removal. For 2004 and later Highlander models, the A/C Switch is mounted to the center trim panel. Pry the panel outwards to disengage the clips and disconnect the wiring to the A/C Switch. Remove the two mounting screws to separate the A/C Switch from the center trim panel, with installation being the reverse of removal. For 2010 and later Lexus models, the radio unit must be removed, as the A/C Switch is incorporated into the radio receiver and navigation unit. Installation is the reverse of removal, followed by running the engine to check for proper functioning of the A/C. For Highlander models, pry the rear A/C Switch out of the center console, disconnect the electrical connectors, and remove the A/C Switch, with installation being the reverse of removal. For 2018 and later Lexus RX350 models, use a trim tool to pry the rear A/C Switch out, slide it towards the front while pulling the panel outwards, disconnect the electrical connectors, and then install the A/C Switch by connecting the electrical connectors and snapping the panel into place. Finally, run the engine to check for proper functioning of the A/C.