Toyota Sequoia (2005). Manual - part 553

I28576

270

°

 

Bright

0

°

 

Dark

R6

ILL–

I28577

Light Control Rheostat 
Wire Harness View:

R6

E

–

DIAGNOSTICS

AUDIO SYSTEM

DI–2007

2201

8

Check light control rheostat.

PREPARATION:
(a)

Reconnect the light control rheostat switch connector.

(b)

Ignition switch is ON.

(c)

Light control switch is TAIL or HEAD.

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

Symbol

(Tester connection)

Condition

Specified condition

ILL– (R6–6) – 

Body ground

Rheostat knob to fully

counterclockwise 

→

 

fully clockwise

Below 1 V 

→

 10 to 14 V

NG

Replace light control rheostat.

OK

9

Check harness and connector (Light control rheostat – Body ground).

PREPARATION:
Disconnect the light control rheostat connector.
CHECK:
Measure the resistance according to the value(s) in the table
below.
OK:

Symbol (Tester connection)

Specified condition

E (R6–5) – Body ground

Below 1 

Ω

NG

Repair or replace harness or connector.

OK

Repair or replace wire harness or connector (Battery – spiral cable sub–assy).

I28378

Radio Receiver Assy

R–W

1

7

R4

MUTE

S10 
Stereo Component Amplifier

MUTE

DI–2008

–

DIAGNOSTICS

AUDIO SYSTEM

2202

Mute signal circuit

CIRCUIT DESCRIPTION

This circuit sends a signal to the stereo component amplifier to mute noise. Because of that, the noise pro-
duced by changing the sound source ceases.
If there is an open in the circuit, noise can be heard from the speakers when changing the sound source.
If there is a short in the circuit, even though the stereo component amplifier assy is normal, no sound or only
an extremely small sound can be produced.

WIRING DIAGRAM

DID9Y–01

I28755

Stereo Component Amplifier Assy:

MUTE

S10

I28606

Radio Receiver Assy 
Wire Harness View:

MUTE

R4

I28752

Stereo Component Amplifier Assy:

MUTE

S10

–

DIAGNOSTICS

AUDIO SYSTEM

DI–2009

2203

INSPECTION PROCEDURE

1

Inspect stereo component amplifier assy.

PREPARATION:
Make sure that the stereo component amplifier assy connector
is connected.
CHECK:
Measure the voltage according to the value in the table below.
OK:

Symbol

(Tester connection)

Condition

Specification

MUTE (S10–1) –

Body ground

Turn ignition switch to

ACC, Audio system is

playing 

→

Changing mode

Above 3.5 V 

→

 Below 1 V

OK

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

DI–1967

).

NG

2

Check harness and connector (Radio receiver assy – Stereo component amplifi-
er assy).

PREPARATION:
Disconnect the radio receiver assy and stereo component am-
plifier assy connector.
CHECK:
Measure the resistance according to the value(s) in the table
below.
OK:

Symbol 

(Tester connection)

Condition

Specified condition

MUTE (R4–7) – 

MUTE (S10–1)

Always

Below 1 

Ω

MUTE (R4–7) – 

Body ground

Always

10 k

Ω 

or higher

NG

Repair or replace harness or connector.

I28738

R4

Wire Harness View:

MUTE

DI–2010

–

DIAGNOSTICS

AUDIO SYSTEM

2204

OK

3

Inspect radio receiver assy.

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

Symbol

(Tester connection)

Condition

Specified condition

MUTE (R4–7) – 

Body ground

Ignition switch ON

Above 3.5 V

OK

Replace stereo component amplifier assy.

NG

Replace radio receiver assy.