Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
Tests for voltage at the battery positive voltage terminal of the horn relay coil.
-
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.
-
The horns need 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 horns. Inspect the circuits for faults that would restrict current flow.
Step | Action | Yes | No |
|---|---|---|---|
1 | Did you perform the Horns Diagnostic System Check? | Go to Step 2 | |
2 | Did you review the Horns operation and perform the necessary inspections? | Go to Step 3 | Go to Symptoms - Horns |
3 | Depress the horn switch. Do the horns operate? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 4 |
4 |
Does the horn relay turn ON and OFF with each command? | Go to Step 12 | Go to Step 5 |
Does the test lamp illuminate? | Go to Step 6 | Go to Step 16 | |
6 |
Does the test lamp illuminate? | Go to Step 7 | Go to Step 13 |
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 14 | 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 23 | Go to Step 20 |
12 | Test the horn switch signal for a short to voltage or open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 23 | Go to Step 22 |
13 | Test the control circuit of the horn relay for a short to voltage or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 23 | Go to Step 22 |
14 |
Does the horn sound? | Go to Step 15 | Go to Step 21 |
Repair the high resistance in the horn control circuit or the horn ground (A resistance as low as 0.5ohms 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 23 | -- | |
16 | 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 23 | -- |
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 23 | -- |
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 23 | -- |
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 23 | -- |
20 | Replace the horn relay. Refer to Relay Replacement in Wiring Systems. Did you complete the replacement? | Go to Step 23 | -- |
21 | Replace the horn assembly. Refer to Horn Replacement . Did you complete the replacement? | Go to Step 23 | -- |
22 | Replace the Body Control Module (BCM). Refer to Body Control Module Replacement in Body Control Systems. Did you complete the replacement? | Go to Step 23 | -- |
23 | Operate the horns. Do the horns operate properly? | System OK | Go to Step 1 |
