Illumination Circuit: Procedure

1. Check if the illumination for the radio and display receiver assembly, steering pad switch assembly, heater control switch or others (hazard switch, transmission control switch, etc.) comes on when the light control switch is turned to the head or tail position.

   Result

   Result	Proceed to
   Illumination comes on for all components except steering pad switch assembly.	A
   Illumination comes on for all components except radio and display receiver assembly.	B
   Illumination comes on only for steering pad switch assembly.	C
   No illumination comes on (radio and display receiver assembly, hazard switch, heater control switch, etc.).	D

B → See step   5 

C → See step   8 

D → See step   9 

A: Go to next step 

1. Disconnect the D20 spiral cable with sensor sub-assembly connector.
2. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   D20-13 (IL+2) - Body ground	Light control switch in the tail or head position	11 to 14 V

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Remove the steering pad switch assembly.
2. Connect a battery positive (+) lead to terminal IL+2 and a negative (-) lead to terminal -DP of the steering pad switch assembly connector.
   Fig 1: Inspecting Steering Pad Switch Assembly

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Check if the illumination for the steering pad switch assembly comes on.

   OK

   Illumination for the steering pad switch assembly comes on.

   TEXT IN ILLUSTRATION
   
   

   *a

   Component without harness connected (Steering Pad Switch Assembly)

   -

   -

NG → See step   11 

OK: Go to next step 

1. Remove the spiral cable with sensor sub-assembly.
2. Measure the resistance according to the value(s) in the table below.
   Fig 2: Measuring Resistance Of Spiral Cable With Sensor Sub-Assembly Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   z9-5 (IL+2) - D20-13 (IL+2)	Center	3 Ω or less
   	2.5 rotations to the left
   	2.5 rotations to the right
   z9-3 (-DP) - D20-11 (-DP)	Center	3 Ω or less
   	2.5 rotations to the left
   	2.5 rotations to the right

3. After setting the spiral cable with sensor sub-assembly to the center position, rotate the spiral cable with sensor sub-assembly 2.5 times clockwise. Then while rotating the spiral cable with sensor sub-assembly 5 times counterclockwise, measure the resistance as shown in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   z9-5 (IL+2) - D20-13 (IL+2)	Always	3 Ω or less
   z9-3 (-DP) - D20-11 (-DP)	Always	3 Ω or less

   NOTE:

   • Press and hold the lock located in the center of the spiral cable with sensor sub-assembly to rotate the spiral cable with sensor sub-assembly.
   • The spiral cable with sensor sub-assembly is an important part of the SRS airbag system. Incorrect removal or installation of the spiral cable with sensor sub-assembly may prevent the airbag from deploying.
   • As the spiral cable with sensor sub-assembly may break, do not rotate the spiral cable with sensor sub-assembly more than the specified amount.
   TEXT IN ILLUSTRATION
   
   

   *a	Component without harness connected (Spiral Cable with Sensor Sub-assembly)
   *b	Steering Pad Switch Assembly Side
   *c	Vehicle Side

NG → See step   10 

OK → REPAIR OR REPLACE HARNESS OR CONNECTOR (SPIRAL CABLE WITH SENSOR SUB-ASSEMBLY - BODY GROUND) 

1. Disconnect the E1 radio and display receiver assembly connector.
2. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   E1-10 (ILL+) - Body ground	Light control switch in the tail or head position	11 to 14 V

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Disconnect the E2 radio and display receiver assembly connector.
2. Disconnect the D9 combination meter assembly connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   E2-5 (ILL-) - D9-4 (ILL-)	Always	Below 1 Ω
   E2-5 (ILL-) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   7