77–1
HORN – HORN SYSTEM
HORN SYSTEM
7700S–01
LOCATION
Low Pitched Horn
High Pitched Horn
Steering Wheel Pad
F Horn Button Switch
Engine Room J/B
Engine Room R/B
F HORN Relay
F HORN Fuse
F P/I H–fuse
B74615
2004 Prius – Preliminary Release (RM1075U)
Author : Date : 1115
77–2
HORN – HORN SYSTEM
7700T–01
SYSTEM DIAGRAM
HORN
1 5
P/I HORN Relay
2 3
MAIN
8 1 1
Horn Button
Battery Low Pitched High Pitched
Switch
Horn Horn
A89874
2004 Prius – Preliminary Release (RM1075U)
Author : Date : 1116
77–3
HORN – HORN SYSTEM
7700U–01
PROBLEM SYMPTOMS TABLE
Symptom Suspected Area See Page
1. HORN fuse 77–4
2. HORN relay 77–4
3. High pitched horn 77–4
Horn does not sound.
4. Low pitched horn 77–4
5. Horn button switch –
6. Wire harness –
2004 Prius – Preliminary Release (RM1075U)
Author : Date : 1117
77–4
HORN – HORN SYSTEM
7700V–01
INSPECTION
1. INSPECT FUSE (HORN)
(a) Measure the HORN fuse resistance.
Resistance: Below 1 Ω
If the result is not as specified, replace the fuse.
B79457
2. INSPECT RELAY (HORN)
(a) Remove the HORN relay from the engine room R/B.
(b) Measure the HORN relay resistance.
1 2 Standard:
3 5
5 Tester Connection Specified Condition
1 2 3–5 10 kΩ or higher
3 Below 1 Ω
3–5
(when battery voltage is applied to terminals 1 and 2)
B60778 If the result is not as specified, replace the relay.
3. INSPECT HIGH PITCHED HORN ASSY
(a) Check operation of the horn.
OK:
Measurement Condition Specified Operation
Battery positive (+) → Terminal 1
Horn sounds
Battery negative (–) → Horn bracket
If the result is not as specified, replace the horn assy.
B72265
4. INSPECT LOW PITCHED HORN ASSY
(a) Check operation of the horn.
OK:
Measurement Condition Specified Operation
Battery positive (+) → Terminal 1
Horn sounds
Battery negative (–) → Horn bracket
If the result is not as specified, replace the horn assy.
B72265
If all the check results are as specified above and the wire harness is normal, replace the horn button switch
(steering wheel pad) (see page 60–20).
2004 Prius – Preliminary Release (RM1075U)
Author : Date : 1118
77–5
HORN – HORN ASSY
HORN ASSY
7700W–01
REPLACEMENT
1. REMOVE FRONT BUMPER COVER (See page 76–2)
2. REMOVE HIGH PITCHED HORN ASSY
(a) Disconnect the connector.
(b) Remove the bolt and horn.
3. REMOVE LOW PITCHED HORN ASSY
(a) Disconnect the connector.
(b) Remove the bolt and horn.
B74616
4. INSTALL HIGH PITCHED HORN ASSY
(a) Place the stay onto the baffle part in the radiator support upper, and then install the horn with the bolt.
Torque: 20 N⋅m (204 kgf⋅cm, 15 ft⋅lbf)
(b) Connect the connector.
5. INSTALL LOW PITCHED HORN ASSY
(a) Place the stay onto the baffle part in the radiator support upper, and then install the horn with the bolt.
Torque: 20 N⋅m (204 kgf⋅cm, 15 ft⋅lbf)
(b) Connect the connector.
2004 Prius – Preliminary Release (RM1075U)
Author : Date : 1119