Screen backlight does not dim/remains dim

WARNING: This page is about a different car, the 2013 Acura MDX, 2012 Acura MDX, 2011 Acura MDX, and 2010 Acura MDX. However, it is still accessible from the selected car via links, so may be relevant.

NOTE:

Check the vehicle battery condition first BATTERY TEST ).
Check the dash and gauge dimmer operation. If there is a problem with the dash and gauge dimmer, repair it before doing this troubleshooting.

Turn the ignition switch to ON (II).
Turn the combination light switch ON and OFF.
Does the screen backlight dim with the combination light switch in the ON position?

YES -Operation is normal at this time.

NO -Go to step 3.
Check the backlight settings in the display set up (refer to the Owner's Manual for more information).
Are the display settings set properly?

YES -Go to step 4.

NO -Adjust the display settings, and recheck.
Turn the ignition switch to LOCK (0).
Check that the rear controller and screen and the audio-navigation unit are properly connected.
Are the connections OK?

YES -Go to step 6.

NO -Reconnect the connector, and recheck.
Turn the ignition switch to ON (II).
Measure the voltage between rear controller and screen 24P connector terminal No. 11 and body ground. Turn the combination light switch on and off to see if the voltage changes.

Fig 1: Measuring Voltage Between 24P Connector Terminal No. 11 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage with the combination light switch ON?

YES -Go to step 9.

NO -Go to step 8.
Check the illumination of several other unit/switches not related to the rear entertainment system.
Are the buttons illuminated?

YES -Repair an open in the wire(s) between the interior light relay in the auxiliary under-hood relay box and the rear controller and screen.

NO -Troubleshoot the interior lights. Start by checking the interior light relay in the auxiliary under-hood relay box. If the relay is OK, check the No. 22 (7.5 A) fuse in the under-hood fuse/relay box. If there is OK, check for open in the wire between the under-hood fuse/relay box and the interior light relay.
Check for continuity between rear controller and screen 24P connector terminal No. 23 and gauge control module connector B (24P) terminal No. 2.

Fig 2: Checking Continuity Between 24P Connector And Connector B (24P)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Replace the rear controller and screen

NO -Repair an open in the wire between the rear controller and screen and the gauge control module.