Toyota Sequoia (2005). Manual - part 623

I28479

Steering 
Pad Switch

Spiral Cable 
Sub–assy

Radio and Navigation Assy

SW2

SWG

SW1

R27

EAU

AU2

AU1

EAU

AU2

AU1

C9–11

GR–R

LG–R

BR–W

C9–12

C9–10

11

12

10

8

7

6

R27

R27

–

DIAGNOSTICS

NAVIGATION SYSTEM

DI–2287

2481

Steering pad switch circuit

CIRCUIT DESCRIPTION

This circuit sends an operation signal from the steering pad switch assy to the radio and navigation assy.
If there is an open in the circuit, the audio system cannot be operated by the steering pad switch assy.
If there is a short in the circuit, the resulting condition is the same as if the switch were continuously de-
pressed. Therefore, the radio and navigation assy cannot be operated by the steering pad switch assy, and
the radio and navigation assy itself cannot function.

WIRING DIAGRAM

DIDDO–01

I28299

SW1

SW2

SWG

R27

DI–2288

–

DIAGNOSTICS

NAVIGATION SYSTEM

2482

INSPECTION PROCEDURE

NOTICE:
The vehicle is equipped with SRS (Supplemental Restraint System) such as airbags. Before servic-
ing (including removal or installation of parts), be sure to read the precautionary notice for the sup-
plemental restraint system (See page 

RS–1

).

1

Inspect radio and navigation assy.

PREPARATION:
Disconnect the radio and navigation assy connector.
CHECK:
Measure the resistance according to the value(s) in the table
below.
OK:

Symbol 

(Tester connection)

Condition

Specified condition

SW1 (R27–7) – 

SWG (R27–6)

No switch is pushed

Approx. 100 k

Ω

SW1 (R27–7) – 

SWG (R27–6)

SEEK+ switch: push

Approx. 0 

Ω

SW1 (R27–7) – 

SWG (R27–6)

SEEK– switch: push

Approx. 0.3 k

Ω

SW1 (R27–7) – 

SWG (R27–6)

VOL+ switch: push

Approx. 1 k

Ω

SW1 (R27–7) – 

SWG (R27–6)

VOL– switch: push

Approx. 3.2 k

Ω

SW2 (R27–8) – 

SWG (R27–6)

No switch is pushed

Approx. 100 k

Ω

SW2 (R27–8) – 

SWG (R27–6)

MODE switch: push

Approx. 0 

Ω

NG

Go to step 2.

OK

Proceed to next circuit inspection shown in problem symptoms table (See page 

DI–2184

).

I28724

EAU

AU2

AU1

C9

–

DIAGNOSTICS

NAVIGATION SYSTEM

DI–2289

2483

2

Inspect steering pad switch assy.

PREPARATION:
Disconnect the steering pad switch assy connector.
CHECK:
Measure the resistance according to the value(s) in the table below.
OK:

Symbol (Tester connection)

Condition

Specified condition

AU1 (C9–12) – EAU (C9–10)

No switch is pushed

Approx. 100 k

Ω

AU1 (C9–12) – EAU (C9–10)

SEEK+ switch: push

Approx. 0 

Ω

AU1 (C9–12) – EAU (C9–10)

SEEK– switch: push

Approx. 0.3 k

Ω

AU1 (C9–12) – EAU (C9–10)

VOL+ switch: push

Approx. 1 k

Ω

AU1 (C9–12) – EAU (C9–10)

VOL– switch: push

Approx. 3.2 k

Ω

AU2 (C9–11) – EAU (C9–10)

No switch is pushed

Approx. 100 k

Ω

AU2 (C9–11) – EAU (C9–10)

MODE switch: push

Approx. 0 

Ω

NG

Replace steering pad switch assy.

OK

I28340

Steering Pad Switch Assy Side:

EAU

AU2

AU1

Vehicle Side:

EAU

AU2

AU1

C9

DI–2290

–

DIAGNOSTICS

NAVIGATION SYSTEM

2484

3

Inspect spiral cable sub–assy.

PREPARATION:
Disconnect the steering pad switch assy and spiral cable sub–
assy connectors.
CHECK:
Measure the resistance according to the value(s) in the table
below.
OK:

Tester connection

Specified condition

EAU – EAU

Below 1 

Ω

AU1 – AU1

Below 1 

Ω

AU2 – AU2

Below 1 

Ω

NG

Replace spiral cable sub–assy.

OK

Repair or replace harness or connector (Radio and navigation assy – spiral cable).