Toyota Sequoia (2005). Manual - part 616

I28324

ACC

E

B+

B2+

GND

S10

S9

–

DIAGNOSTICS

NAVIGATION SYSTEM

DI–2259

2453

INSPECTION PROCEDURE

1

Inspect stereo component amplifier assy (B+, B2+, ACC, GND, E).

PREPARATION:
Disconnect the stereo component amplifier assy connectors.
CHECK:
Measure the resistance according to the value(s) in the table
below.
OK:

Symbol 

(Tester connection)

Condition

Specified condition

E (S9–16) – Body ground

Always

Below 1 

Ω

GND (S9–15) – 

Body ground

Always

Below 1 

Ω

CHECK:
Measure the voltage according to the value(s) in the table be-
low.
OK:

Symbol 

(Tester connection)

Condition

Specified condition

B+ (S9–1) – GND (S9–15)

Always

10 to 14 V

B2+ (S9–10) –
 GND (S9–15)

Always

10 to 14 V

ACC (S10–12) – 

GND (S9–15)

Ignition SW ACC

10 to 14 V

NG

Repair or replace harness or connector.

OK

Proceed to next circuit inspection shown in problem symptoms table or diagnostic trouble code
chart (See page 

DI–2203

 or 

DI–2184

).

I28766

R6 
Light Control 
Rheostat Assy

Radio and Navigation Assy

J/C

Steering Pad Switch Assy

Spiral Cable 
Sub–assy

From 
TAILLIGHT 
Relay

ILL–

SWG

J/C

ILL+

W–G

G

J39

J40

J39

J40

J39

J40

W–G

G

G

G

A

B

A

A

A

B

ILL–

T

12

2

6

1

10

C9–1

BR–W

C9–10

6

4

Steering SW

R30

R27

R30

DI–2260

–

DIAGNOSTICS

NAVIGATION SYSTEM

2454

Illumination circuit

CIRCUIT DESCRIPTION

Power is supplied to the radio and navigation panel illumination when the light control switch is in the TAIL
or HEAD position. The body ECU determines the external brightness based on the brightness level detected
by the automatic light control sensor, and then operates the TAILLIGHT relay. Power can also be supplied
by operating the relay.
The intensity of the radio receiver panel illumination can be adjusted by the rheostat switch.

WIRING DIAGRAM

DIDDF–01

–

DIAGNOSTICS

NAVIGATION SYSTEM

DI–2261

2455

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

Check illumination.

CHECK:
Check if the illumination for the radio and navigation assy, steering pad switch assy or others (A/C switch,
cigarette lighter, etc.) comes on when the light control switch is turned to the HEAD or TAIL position.
RESULT:

Components with illumination

Go to step

Illumination comes on for all components except radio and navigation assy.

A

Illumination comes on for all components except steering pad switch.

B

Illumination comes on for all components except radio and navigation assy,

steering pad switch, Rear heater control panel, each switch, etc.

C

All illumination does not come on. (Radio and navigation assy, steering pad

switch, Combination meter, Rear heater control panel, each switch, etc.)

D

HINT:
If the illuminations have malfunctions, check the rheostat switch.

B

Go to step 4.

C

Go to step 8.

D

Go to combination meter system 
(See page 

DI–1645

).

A

I28747

R30

ILL+

DI–2262

–

DIAGNOSTICS

NAVIGATION SYSTEM

2456

2

Check radio and navigation assy (ILL+).

PREPARATION:
Disconnect the radio and navigation assy connector.
CHECK:
Measure the voltage according to the value(s) in the table be-
low.
OK:

Symbol 

(Tester connection)

Condition

Specified condition

ILL+ (R30–2) – 

Body ground

Light control switch TAIL

10 to 14 V

NG

Repair or replace wire harness or connector
(Radio and navigation assy – battery).

OK