Audio unit button does not work (without 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) (WITHOUT NAVIGATION) )

Operate all items in the appropriate switch list
Switch list

AM/FM, XM, CD, AUX, TITLE, CLOCK, Preset 1-6, CATEGORY+/-, SKIP, SCAN, A SEL, RETURN, SET UP, , SEL, VOL

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

YES -Operation is normal

NO -Substitute a known-good audio unit (see AUDIO UNIT REMOVAL/INSTALLATION ) If the symptom/indication goes away, replace the original audio unit