Audio switch panel button illumination 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

Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode
Turn the combination lighting switch to the parking light position
Check the illumination of the audio unit buttons
Are the buttons illuminated?

YES -Intermittent problem, the audio unit is OK at this time Check for loose or poor connections at audio unit connector A (24P)

NO -Go to step 4
Check the illumination of several other buttons not related to the audio system
Are the buttons illuminated?

YES -Go to step 5

NO -Troubleshoot the interior lights Start by checking the No 6 (7 5 A) fuse in the passenger's under-dash fuse/relay box If the fuse is OK, check for an open in the wire between the passenger's under-dash fuse/relay box and the audio unit
Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode
Disconnect audio unit connector A (24P)
NOTE: Eject all the CDs before removing the audio unit to prevent damaging the CD player's load mechanism
Disconnect the gauge control module 32P connector
Check for continuity between audio unit connector A (24P) terminal No 1 and gauge control module 32P connector terminal No 8

Fig 1: Checking Continuity Between Audio Unit Connector A (24P) Terminal And Gauge Control Module 32P Connector Terminal
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Go to step 9

NO -Repair open in the wire between the gauge control module and the audio unit
Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode
With the headlight switch still on, measure the voltage between audio unit connector A (24P) terminal No 13 and body ground

Fig 2: Measuring Voltage Between Audio Unit Connector A (24P) Terminal No 13 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?

YES -Check the connections at audio unit connector A (24P) If all connections are OK, replace the audio unit (see AUDIO UNIT REMOVAL/INSTALLATION )

NO -Repair open in the wire between the passenger's under-dash fuse/relay box and the audio unit