Illumination Circuit: Procedure

1. Check if the illumination for the navigation receiver assembly, steering pad switch, glove box or other parts (hazard switch, transmission control switch, etc.) come 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.	A
   Illumination comes on for all components except navigation receiver assembly.	B
   No illumination comes on (navigation receiver, hazard switch, glove box, etc.).	C
   Illumination comes on for all components except steering pad switch and navigation receiver assembly.	D

B → See step   6 

C → See step   8 

D → See step   7 

A: Go to next step 

1. Disconnect the D21 spiral cable sub-assembly connector.
   Fig 1: Checking Harness And Connector (Spiral Cable - Battery)

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

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   D21-12 (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. Remove the steering pad switch assembly. Refer to REMOVAL .
   Fig 2: Inspecting Steering Pad Switch Assembly

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   TEXT IN ILLUSTRATION
   
   

   *1

   Component without harness connected (Steering Pad Switch Assembly)

   -

   -

2. Connect the positive (+) lead of the battery to terminal z2-5 (IL+2) and the negative (-) lead of the battery to terminal z2-8 (EAU) of the steering pad switch assembly connector.
3. Check if the illumination for the steering pad switch assembly comes on.

   OK

   Illumination for the steering pad switch assembly comes on.

NG → See step   9 

OK: Go to next step 

1. Remove the spiral cable sub-assembly. Refer to REMOVAL .
   Fig 3: Inspecting Spiral Cable Sub-Assembly

   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) - D21-4 (EAU)	Spiral cable is turned 2.5 rotations counterclockwise	Below 1 Ω
   	Spiral cable is centered
   	Spiral cable is turned 2.5 rotations clockwise
   z2-5 (IL+2) - D21-12 (IL+2)	Spiral cable is turned 2.5 rotations counterclockwise
   	Spiral cable is centered
   	Spiral cable is turned 2.5 rotations clockwise

   TEXT IN ILLUSTRATION
   
   

   *1	Component without harness connected (Spiral Cable Sub-Assembly)
   *a	Steering Pad Switch Assembly Side
   *b	Vehicle Wire Harness Side

   WARNING:

   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 Precaution in the SRS. Refer to PRECAUTION .

NG → See step   10 

OK: Go to next step 

1. Disconnect the D56 navigation receiver assembly connector.
2. Disconnect the D21 spiral cable sub-assembly connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   D56-6 (SWG) - D21-4 (EAU)	Always	Below 1 Ω
   D56-6 (SWG) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   11 

1. Disconnect the D52 navigation receiver assembly connector.
   Fig 4: Checking Harness And Connector (Navigation Receiver - Battery)

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

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   D52-2 (ILL+) - Body ground	Light control switch TAIL or HEAD	11 to 14 V

   TEXT IN ILLUSTRATION
   
   

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

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   11 

1. Disconnect the D52 navigation receiver assembly connector.
2. Disconnect the D18 combination meter assembly connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   D52-12 (ILL-) - D18-18 (ILL-)	Always	Below 1 Ω
   D52-12 (ILL-) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   11