Audio unit button does not work (with navigation)

WARNING: This page is about a different car, the 2011 Acura TL, 2010 Acura TL, and 2009 Acura TL. However, it is still accessible from the selected car via links, so may be relevant.

NOTE:

Check the vehicle battery condition first (see BATTERY TEST )
Check the connectors for poor connections or loose terminals
In order to troubleshoot the main power switch, go to Power switch will not turn on (see AUDIO UNIT POWER SWITCH WILL NOT TURN ON (NO INFORMATION DISPLAY AND NO SOUND) (WITH NAVIGATION) )

Operate all items in the appropriate switch list
Switch list

AM/FM, XM, TITLE, , DISC, HDD/AUX, Preset 1-6, CATEGORY+/-, SKIP, TUNE, SCAN, A SEL, AUDIO, VOL

Do all the items in the appropriate switch list work properly?

YES -Operation is normal

NO -Substitute a known-good audio-navigation unit (including the HDD) (see AUDIO-NAVIGATION UNIT REMOVAL/INSTALLATION ) If the symptom/indication goes away, replace the audio-navigation unit If the symptom still present, substitute a known-good audio-navigation switch panel (see AUDIO-NAVIGATION SWITCH PANEL REMOVAL/INSTALLATION ), and recheck. If the symptom/indication goes away, replace the audio-navigation switch panel