Test Description
The number(s) below refer to the step number(s) 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 horns need maximum current flow to operate properly. A high resistance (greater than 0.5ohms) in the horn control circuit or the horn ground circuit could cause operating problems with the horns. Inspect the circuits for faults that would restrict current flow.
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The horn relay control circuit includes the 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. Do the horns 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 15 | |
6 |
Does the test lamp illuminate? | Go to Step 7 | Go to Step 16 |
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 17 | |
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. Do the horns operate? | Go to Step 11 | Go to Step 9 |
9 |
Does the test lamp illuminate? | Go to Step 10 | Go to Step 18 |
10 |
Does the test lamp illuminate? | Go to Step 12 | Go to Step 19 |
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 22 | Go to Step 20 |
12 | Inspect for poor connections at the horn. 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 22 | Go to Step 13 |
13 |
Does the horn sound? | Go to Step 14 | Go to Step 21 |
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.) Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 22 | -- | |
15 | 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 22 | -- |
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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. To disable the SIR system, refer to Disabling the SIR System in SIR. Repair the open or short to voltage in the horn relay control circuit. (The horn relay control circuit includes the horn slip ring and the horn switch.) Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 22 | -- | |
17 | 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 22 | -- |
18 | 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 22 | -- |
19 | 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 22 | -- |
20 | Replace the horn relay. Refer to Horn Relay Replacement . Did you complete the replacement? | Go to Step 22 | -- |
21 | Replace the horn assembly. Refer to Horn Replacement . Did you complete the replacement? | Go to Step 22 | -- |
22 | Operate the horns. Do the horns operate properly? | System OK | Go to Step 1 |
