Horn Circuit

THEFT DETERRENT SYSTEM: Horn Circuit

Horn Circuit

DESCRIPTION

When the theft deterrent system is switched from the armed state to the alarm sounding state, the multiplex network body ECU turns on the HORN relay, causing the vehicle's horns to sound at intervals of 0.4 seconds.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK HORN ASSEMBLY
(a) Press the horn switch and check if the horns sound.
(1) If the horns sound, proceed to A.
(2) If the horns do not sound, proceed to B.
B -- CHECK WIRE HARNESS (ENGINE ROOM R/B - BATTERY)
A -- REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY
2. CHECK WIRE HARNESS (ENGINE ROOM R/B - BATTERY)





(a) Disconnect the 1A J/B connector.
(b) Measure the voltage of the wire harness side connector.
Standard voltage:





NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.
3. CHECK HORN ASSEMBLY
(a) Connect terminals 3 and 5 of the HORN relay on the engine room J/B side and check if the horns sound normally.
(1) If the high and low pitched horns sound, proceed to A.
(2) If only the low pitched horn sounds, proceed to B.
(3) If only the high pitched horn sounds, proceed to C.
(4) If the high and low pitched horns do not sound, proceed to D.
D -- CHECK HORN ASSEMBLY
C -- REPLACE LOW PITCHED HORN ASSEMBLY
B -- REPLACE HIGH PITCHED HORN ASSEMBLY
A -- Continue to next step.
4. INSPECT FUSE (HORN)
(a) Remove the HORN fuse from the engine room J/B.
(b) Measure the resistance of the fuse.
Standard resistance:
Below 1 Ohms
NG -- REPLACE FUSE
OK -- Continue to next step.
5. INSPECT HORN RELAY





(a) Remove the HORN relay from the engine room J/B.
(b) Measure the resistance of the relay.
Standard resistance:





NG -- REPLACE HORN ASSEMBLY
OK -- Continue to next step.
6. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY





(a) Disconnect the 2C J/B connector.
(b) Measure the voltage of the wire harness side connector.
Standard voltage:





NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY
7. CHECK HORN ASSEMBLY





(a) Disconnect the H8 and H9 connectors.
(b) Measure the voltage of the wire harness side connectors.
Standard voltage:





NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- REPLACE HORN ASSEMBLY