Illumination Circuit: Procedure

1. Check if the illumination for the radio 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

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

B → See step   7 

C → See step   9 

A: Go to next step 

1. Disconnect the spiral cable connector.
2. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   D16-12 (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. Disconnect the steering pad switch assembly connector.
2. Connect a battery positive (+) lead to terminal IL+2 and a negative (-) lead to terminal EAU 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   10 

OK: Go to next step 

1. Disconnect the steering pad switch assembly and spiral cable connectors.
   Fig 2: Inspecting Spiral Cable

   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
   z2-8 (EAU) - D16-4 (EAU)	Center	Below 1 Ω
   	2.5 rotations to the left
   	2.5 rotations to the right
   z2-5 (IL+2) - D16-12 (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. Be sure to read the pages shown in the brackets.

   HINT: 

   • Removal, refer to REMOVAL
   • Installation, refer to INSTALLATION
   TEXT IN ILLUSTRATION
   
   

   *a	Component without harness connected (Spiral Cable)
   *b	Steering Pad Switch Assembly Side
   *c	Vehicle Side

NG → See step   11 

OK: Go to next step 

1. Disconnect the radio receiver assembly and spiral cable connectors.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   E3-6 (SWG) - D16-4 (EAU)	Always	Below 1 Ω
   E3-6 (SWG) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   6 

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

   Standard Voltage

   W/ BACK DOOR SPEAKER
   
   

   Tester Connection	Condition	Specified Condition
   E2-2 (ILL+) - Body ground	Light control switch in the tail or head position	11 to 14 V

   W/O BACK DOOR SPEAKER
   
   

   Tester Connection	Condition	Specified Condition
   E8-10 (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 radio receiver assembly and combination meter assembly connectors.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   W/ BACK DOOR SPEAKER
   
   

   Tester Connection	Condition	Specified Condition
   E2-12 (ILL-) - E1-30 (ILL-)	Always	Below 1 Ω
   E1-30 (ILL-) - Body ground	Always	10 kΩ or higher
   E1-40 (E2) - Body ground	Always	Below 1 Ω

   W/O BACK DOOR SPEAKER
   
   

   Tester Connection	Condition	Specified Condition
   E9-5 (ILL-) - E1-30 (ILL-)	Always	Below 1 Ω
   E1-30 (ILL-) - Body ground	Always	10 kΩ or higher
   E1-40 (E2) - Body ground	Always	Below 1 Ω

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   6