Toyota Tundra. Manual — part 380

2009 ACCESSORIES AND EQUIPMENT

Horn - Tundra

HORN SYSTEM

PARTS LOCATION

Fig. 1: Identifying Horn System Parts Location
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

2009 Toyota Tundra

2009 ACCESSORIES AND EQUIPMENT Horn - Tundra

2009 Toyota Tundra

2009 ACCESSORIES AND EQUIPMENT Horn - Tundra

SYSTEM DIAGRAM

Fig. 2: Horn System Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

PROBLEM SYMPTOMS TABLE

HINT:

Use the table below to help determine the cause of the problem symptom. The potential causes of the symptoms
are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking
the suspected areas in the order they are listed. Replace parts as necessary.

2009 Toyota Tundra

2009 ACCESSORIES AND EQUIPMENT Horn - Tundra

Horn system

HORN SYMPTOMS REFERENCE

HORN RELAY

ON-VEHICLE INSPECTION

1. DISCONNECT CABLE FROM NEGATIVE BATTERY TERMINAL

2. REMOVE INTEGRATION RELAY (UNIT E)

a. Remove the engine room relay block cover.

Fig. 3: Removing Engine Room Relay Block Cover
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

b. Using a screwdriver, detach the 2 claws and disconnect the integration relay from the engine room

relay block.

Symptom

Suspected Area

See

Horn does not sound

HORN fuse

HORN RELAY

Low pitched horn

HORN RELAY

High pitched horn

HIGH PITCHED HORN

Engine room relay block, junction block (HORN relay)

HORN RELAY

Steering pad assembly

-

Spiral cable

-

Wire harness

-

NOTE:



Some systems need to be initialized after the cable is reconnected
(see INITIALIZATION ).



After the ignition switch is turned OFF, the navigation system
requires approximately 90 seconds to record various types of
memory and settings. As a result, after turning the ignition switch
OFF, wait 90 seconds or more before disconnecting the cable from
the negative (-) battery terminal.

2009 Toyota Tundra

2009 ACCESSORIES AND EQUIPMENT Horn - Tundra

HINT:

Tape the screwdriver tip before use.

c. Disconnect the 3 connectors.

3. INSPECT INTEGRATION RELAY (HORN RELAY)

a. Measure the resistance of the HORN fuse.

1. Measure the resistance according to the value(s) in the table below.

Standard resistance

RESISTANCE REFERENCE

NOTE:



Some relays are built into the integration relay (unit E). The integration
relay cannot be disassembled. If there is a malfunction in the circuit of the
integration relay, replace the integration relay.



The internal circuit of the integration relay is as shown in the illustration
below. Inspect the integration relay using the following procedures.

Fig. 4: Engine Room Relay Circuit Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

Tester Connection Condition Specified Condition

HORN fuse

Always

Below 1 ohms

2009 Toyota Tundra

2009 ACCESSORIES AND EQUIPMENT Horn - Tundra