HO
HO
HO
HO HORN
HORN
HORN
HORN
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Diagnosis
Diagnosis
Diagnosis
Diagnosis and
and
and
and Testing
Testing
Testing
Testing
Troubleshooting
Troubleshooting
Troubleshooting
Troubleshooting
2. Horn failed to work.
Step Operation
Yes
No
1 Is the vehicle equipped with any anti-theft system? Go to Step 2. Go to Step 3.
2 I s the vehicle diagnostic system check performed? Go to Step 4.
C heck vehicle
diagnostic system.
3 I s horn operation and other necessary inspection performed? Go to Step 4. Check horn harness.
4
P ress and then release the horn botton.
Is the horn always on?
Check horn harness. Go to Step 5.
5
1. Disconnect the horn relay.
2. Connect a test lamp between the positive battery voltage circuit of horn
relay coil and a sound ground.
Is the test lamp lit?
Go to Step 6. Go to Step 13.
6
1. Connect a test lamp between the positive battery voltage circuit of horn
relay coil and the horn relay control circuit.
2. Press the horn button and hold it.
Is the test lamp lit?
Go to Step 7. Go to Step 14.
7
Connect a test lamp between the positive battery voltage circuit of horn
relay button and a sound ground.
Is the test lamp lit?
Go to Step 8. Go to Step 15.
8
Connect a jumper with a 15A fuse between the positive battery voltage
circuit of horn relay button and the horn control circuit.
D oes the horn ring?
Go to Step 11. Go to Step 9.
9
1. Reconnect the horn relay.
2. Disconnect the horn connector.
3. Connect a test lamp between the horn control circuit and a sound
ground.
4. Press the horn button and hold it.
Is the test lamp lit?
Go to Step 10. Go to Step 16.
10
1. Connect a test lamp between the horn control circuit and the horn
ground circuit.
2. Press the horn button and hold it.
Is the test lamp lit?
Go to Step 12. Go to Step 17.
12
Perform troubleshooting for the high impedence in the horn control circuit
or horn ground circuit.
Is the maintenance finished?
Go to Step 19. —
13
Perform troubleshooting for the open circuit or high impedence in the
positive battery voltage circuit of horn relay coil.
Is the maintenance finished?
Go to Step 19. —
14
Perform troubleshooting for the open circuit in horn relay control circuit or
shorted positive battery circuit. H orn relay control circuit is composed of
horn slip ring and horn button.
Is the maintenance finished?
Go to Step 19. —
15
Perform troubleshooting for the open circuit or high impedence in the
positive battery voltage circuit of horn relay button.
Is the maintenance finished?
Go to Step 19. —
16
Perform troubleshooting for the open circuit or high impedence in the horn
control circuit.
Is the maintenance finished?
Go to Step 19. —
17
Perform troubleshooting for the open circuit or high impedence in the horn
ground circuit.
Is the maintenance finished?
Go to Step 19. —
18
Replace the horn relay.
Is the replacement finished?
Go to Step 19. —
19
O perate the horn.
Is the horn able to operate normally?
System is normal. Go to Step 1
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