SERVICE INFORMATION NOTE: If the information below determines both parts need replacement, do not replace them at different times. Make sure both parts are replaced at the same time. Audio unit (with display) replacement: Whenever an audio unit on an applied vehicle is replaced for any reason, check the part number (P/N) of the A/C switch assembly (A/C Controller Assembly). A/C switch assembly (A/C controller assembly) replacement: Whenever an A/C switch assembly on an applied vehicle is replaced for any reason, check the P/N of the audio unit. Please see this bulletin for further information.