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

   Result	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
   Illumination comes on for all components except integration control and panel assembly.	C
   No illumination comes on (radio receiver assembly, hazard switch, heater control switch, etc.).	D
   Illumination comes on only for steering pad switch assembly.	E

B → See step   6 

C → See step   8 

D → See step   12 

E → See step   11 

A: Go to next step 

1. Disconnect the spiral cable sub-assembly connector.
   Fig 1: Identifying Spiral Cable Sub-Assembly Connector Terminals

   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
   J24-12 (IL+2) - Body ground	Light control switch tail or head	11 to 14 V

   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to Spiral 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 battery positive (+) lead to terminal IL+2 and a negative (-) lead to terminal EAU of the steering pad switch assembly connector.
   Fig 2: Identifying Steering Pad Switch Assembly Connector End View

   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   14 

OK: Go to next step 

1. Disconnect the steering pad switch assembly and spiral cable sub-assembly connectors.
   Fig 3: View Of Spiral Cable And Steering Pad Switch Connector Terminals

   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
   k1-8 (EAU) - J24-4 (EAU)	Center	Below 1 Ω
   	2.5 rotations to the left
   	2.5 rotations to the right
   k1-5 (IL+2) - J24-12 (IL+2)	Center	Below 1 Ω
   	2.5 rotations to the left
   	2.5 rotations to the right

   NOTE:

   The spiral cable sub-assembly is an important part of the SRS airbag system. Incorrect removal or installation of the spiral cable sub-assembly may prevent the airbag from deploying. Be sure to read the information shown in the brackets.

   HINT: 

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

   *1	Steering Pad Switch Assembly Side
   *2	Vehicle Side

NG → See step   13 

OK: Go to next step 

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   J108-6 (SWG) - J24-4 (EAU)	Always	Below 1 Ω
   J108-6 (SWG) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   10 

1. Disconnect the radio receiver assembly connector.
   Fig 4: Identifying Radio Receiver Connector Terminals

   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
   J107-2 (ILL+) - Body ground	Light control switch tail or head	11 to 14 V

   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to Radio Receiver Assembly)

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

   Tester Connection	Condition	Specified Condition
   J107-12 (ILL-) - J35-9 (ILL-)	Always	Below 1 Ω
   J35-9 (ILL-) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   10 

1. Disconnect the integration control and panel assembly connector.
   Fig 5: Identifying J54 Terminal 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
   J54-3 (ILL+) - Body ground	Light control switch tail or head	11 to 14 V

   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to Integration Control and Panel Assembly)

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Disconnect the integration control and panel assembly and the combination meter assembly connectors.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   J54-10 (ILL-) - J35-9 (ILL-)	Always	Below 1 Ω
   J54-10 (ILL-) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   15