Illumination Circuit: Procedure

1. Check if the illumination for the display and navigation module display, multi-display, steering pad switch, glove box 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
   No illumination comes on (radio receiver assembly, hazard switch, glove box, etc.).	B

B → See step   6 

A: Go to next step 

1. Disconnect the spiral with sensor cable sub-assembly connector.
   Fig 1: Spiral With Sensor Cable Sub-Assembly Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   F40-12 (IL+2) - Body ground	Light control switch in tail or head	11 to 14 V

   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to Spiral with Sensor Cable Sub-assembly)

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Disconnect the steering pad switch assembly connector.
   Fig 2: Steering Pad Switch Assembly Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   z5-8 (EAU) - F40-4 (EAU)	Center	Below 1 Ω
   	2.5 rotations to the left
   	2.5 rotations to the right
   z5-5 (IL+2) - F40-12 (IL+2)	Center	Below 1 Ω
   	2.5 rotations to the left
   	2.5 rotations to the right

   NOTE:

   The spiral cable is an important part of the SRS airbag system. Incorrect removal or installation of the spiral cable may prevent the airbag from deploying. Refer to information shown in the brackets.

   HINT: 

   • Removal. Refer to REMOVAL
   • Installation. Refer to INSTALLATION
   TEXT IN ILLUSTRATION
   
   

   *1	Component without harness connected (Spiral with Sensor Cable Sub-assembly)
   *2	Steering Pad Switch Side
   *3	Vehicle Side

NG → See step   8 

OK: Go to next step 

1. Disconnect the display and navigation module display connector.
   Fig 3: Display And Navigation Module Display Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Disconnect the spiral with sensor cable sub-assembly connector.
   Fig 4: Spiral With Sensor Cable Sub-Assembly Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   G4-23 (SWG) - F40-4 (EAU)	Always	Below 1 Ω
   G4-23 (SWG) - Body ground	Always	10 kΩ or higher

   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to Display and Navigation Module Display)
   *2	Front view of wire harness connector (to Spiral with Sensor Cable Sub-assembly)

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Disconnect the steering pad switch assembly connector.
2. Connect a positive (+) lead to terminal IL+2 and a negative (-) lead of a 12 V battery to terminal EAU of the steering pad switch assembly connector.
   Fig 5: Steering Pad Switch Assembly Connector

   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
   
   

   *1	Component without harness connected (Steering Pad Switch Assembly)

NG → See step   7 

OK → See step   9