Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Screen backlight does not dim/remains dim (2017 2018 2019 2020)
- Check the vehicle battery condition first - Refer to: Battery Test (2014 2015), or Battery Test (2016) .
- Check the dashlights brightness control knob dimmer operation. If there is a problem with the dash and gauge control module dimmer, repair it before doing this troubleshooting.
- Problem verification
-1. Turn the vehicle to the ON mode.
- 2. Turn the combination light switch on and off then back on.
Does the screen backlight dim with the combination light switch in the on position?
YES
Intermittent failure, the system is OK at this time.
NO
Go to step 2.
- Determine possible failure area (backlight settings, others)
-1. 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 3.
NO
Adjust the display settings, and recheck.
- Determine possible failure area (backlight settings, others)
-1. 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.
- Determine possible failure area (Interior lights circuit, others)
-1. Check the illumination of several other unit/switches not related to the rear entertainment system.
Are the buttons illuminated?
YES
Go to step 5.
NO
Troubleshoot the interior lights.
- Shorted wire check (ILLUMI+ lines)
-1. Disconnect the following connectors.
Rear controller and screen connector A (24P) - 2. Turn the combination lighting switch to the parking light position.
- 3. the voltage between test points 1 and 2.
Test condition Vehicle ON mode Rear controller and screen connector A (24P) : disconnected Test point 1 Rear controller and screen connector A (24P) No. 21 - Refer to: Rear Controller and Screen Connector for Inputs and Outputs (UltraWide RES Type), or Rear Controller and Screen Connector for Inputs and Outputs (RES Type) Test point 2 Body ground Is there battery voltage?
YES
Go to step 6.
NO
Repair an open in the wire.
- Open wire check (ILLUMI- (LED) line)
-1. Turn the combination light switch off.
- 2. Turn the vehicle to the OFF (LOCK) mode.
- 3. Disconnect the following connectors.
Gauge control module connector A (32P) - 4. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode Rear controller and screen connector A (24P) : disconnected Test circuit ILLUMI- (LED) Test point 1 Gauge control module connector A (32P) No. 13 - Refer to: Gauge Control Module Input Test (2014 2015), or Gauge Control Module Input Test (2017 2018 2019 2020), or Gauge Control Module Input Test (2016) Test point 2 Rear controller and screen connector A (24P) No. 22 - Refer to: Rear Controller and Screen Connector for Inputs and Outputs (UltraWide RES Type), or Rear Controller and Screen Connector for Inputs and Outputs (RES Type) Is there continuity?
YES
Replace the rear controller and screen - Refer to: Rear Controller and Screen Removal and Installation (UltraWide RES Type), or Rear Controller and Screen Removal and Installation (RES Type) .
NO
Repair an open in the wire.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.