Test Description
The numbers below refer to the step numbers on the diagnostic table.
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Tests for voltage at the battery positive voltage terminal of the horn relay coil.
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Tests for voltage at the battery positive voltage terminal of the horn relay switch. The HORN fuse supplies power to the battery positive voltage terminal of the horn relay switch.
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The horn needs maximum current flow to operate properly. A high resistance, greater than 0.5 ohms, in the horn control circuit or the horn ground circuit could cause operating problems with the horn. Inspect the circuits for faults that would restrict current flow.
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The horn relay control circuit includes horn slip ring and the horn switch. The horn switch is part of the inflatable restraint steering wheel module. The horn slip ring and the horn switch must be tested for a high resistance, an open or a short to voltage when testing the relay control circuit.
Step | Action | Yes | No |
|---|---|---|---|
1 | Is the vehicle equipped with content theft deterrent (UA6)? | Go to Step 2 | Go to Step 3 |
2 | Did you perform the Horns Diagnostic System Check? | Go to Step 4 | |
3 | Did you review the horns operation and perform the necessary inspections? | Go to Step 4 | Go to Symptoms - Horns |
4 | Depress the horn switch. Does the horn operate? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 5 |
Does the test lamp illuminate? | Go to Step 6 | Go to Step 13 | |
6 |
Does the test lamp illuminate? | Go to Step 7 | Go to Step 14 |
Connect a test lamp between the battery positive voltage circuit of the horn relay switch and a good ground. Does the test lamp illuminate? | Go to Step 8 | Go to Step 15 | |
8 | Momentarily connect a 15 amp fused jumper wire between the battery positive voltage circuit of the horn relay switch and the horn control circuit. Does the horn operate? | Go to Step 11 | Go to Step 9 |
9 |
Does the test lamp illuminate? | Go to Step 10 | Go to Step 16 |
10 |
Does the test lamp illuminate? | Go to Step 12 | Go to Step 17 |
11 | Inspect for poor connections at the horn relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 19 | Go to Step 18 |
Repair the high resistance in the horn control circuit or the horn ground circuit. A resistance as low as 0.5 ohms could cause operating problems with the horns. Also, though unlikely, it is possible that both horns are defective. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 19 | -- | |
13 | Repair the open or high resistance in the battery positive voltage circuit of the horn relay coil. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 19 | -- |
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Important:: The horn switch is part of the inflatable restraint steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement in SIR.
Did you complete the repair? | Go to Step 19 | -- | |
15 | Repair the open or high resistance in the battery positive voltage circuit of the horn relay switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 19 | -- |
16 | Repair the open or high resistance in the horn control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 19 | -- |
17 | Repair the open or high resistance in the horn ground circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 19 | -- |
18 | Replace the horn relay. Did you complete the replacement? | Go to Step 19 | -- |
19 | Operate the horn. Does the horn operate properly? | System OK | Go to Step 1 |
