Even though Headlights are Turned on Head-unit does not Dim the Display [10/2022 - ]: Procedure

1. Select settings icon from the screen.
2. Select "Display" from the "Settings" menu screen.
3. Select "Screen" to display the settings screen.
4. Turn the light control switch to the tail or head position.
5. Check that the "Automatic" setting on the display adjustment screen is set to on.

   Result

   Result	Proceed to
   "Automatic" setting is set to off.	A
   "Automatic" setting is set to on.	B

Result: 

A 

CHANGE "Automatic" SCREEN SETTING TO ON 

Result: 

B 

See step  2

1. Check the rheostat setting.

   Result

   Result	Proceed to
   Set to maximum brightness	A
   Set to other than maximum brightness	B

Result: 

A 

SET RHEOSTAT SETTING OTHER THAN MAXIMUM BRIGHTNESS 

Result: 

B 

See step  3

1. Enter diagnostic mode.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Refer to DIAGNOSIS SYSTEM [10/2022 - 10/2023] , or refer to DIAGNOSIS SYSTEM [10/2023 - ]

2. Select "Function Check/Setting" from the "Service Menu" screen.
3. Select "System Sensors Check" from the "Function Check/Setting I" screen.
4. Operate the light control switch and check that the display changes between ON and OFF accordingly.

   OK

   TAIL
   
   

   Condition	Display
   Light control switch OFF	OFF
   Light control switch TAIL or HEAD	ON

   ADIM/TCAN
   
   

   Condition	Display
   Ignition switch ON, Light control switch TAIL or HEAD, Automatic light control sensor is covered by hand	Dimmed
   Ignition switch ON, Light control switch TAIL or HEAD, Automatic light control sensor is not covered by hand	Not dimmed

   HINT: 

   This display is updated once per second.

   Result

   Result	Proceed to
   Normal	A
   TAIL signal malfunction	B
   The multi-display assembly does not function normally	C
   ADIM/TCAN signal malfunction	D

Result: 

A 

REPLACE RADIO RECEIVER ASSEMBLY. Refer to  REMOVAL [10/2022 - ] 

Result: 

C 

See step  5

Result: 

D 

GO TO CAN COMMUNICATION SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2020 - 10/2023]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2023 - ] 

Result: 

B 

See step  4

1. Disconnect the G52 radio receiver assembly connector.
2. Measure the resistance according to the value(s) in the table below.
   STANDARD RESISTANCE
   
   

   Tester Connection	Condition	Specified Condition
   G52-1 (GND1) - Body ground	Ignition switch ON, Light control switch TAIL or HEAD	Below 1 Ω

3. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   G52-25 (ILL+) - Body ground	Ignition switch ON, Light control switch TAIL or HEAD	11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE RADIO RECEIVER ASSEMBLY. Refer to  REMOVAL [10/2022 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

1. Disconnect the I18 multi-display connector.
2. Measure the resistance according to the value(s) in the table below.
   STANDARD RESISTANCE
   
   

   Tester Connection	Condition	Specified Condition
   I18-13 (GND1) - Body ground	Power switch on (IG), Light control switch TAIL or HEAD	Below 1 Ω

3. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   I18-2 (ILL+) - Body ground	Power switch on (IG), Light control switch TAIL or HEAD	11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE MULTI-DISPLAY. Refer to  REMOVAL [10/2022 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR