For 1990-2009 cars

### Test Description

The number below refers to the step number on the diagnostic table.

1. Tests if ground is constantly being applied to the horn relay.

Step | Action | Yes | No
--- | --- | --- | ---
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 | Depress and release the horn switch. Are the horns ON at all times? | Go to Step 3 | Go to Testing for Intermittent Conditions and Poor Connections
3 | Disconnect the body control module (BCM). Are the horns ON at all times? | Go to Step 4 | Go to Step 8
4 | Disconnect the horn relay. Are the horns ON at all times? | Go to Step 10 | Go to Step 5
5 | Connect a test lamp between the battery positive voltage circuit of the horn relay coil and the horn relay control circuit. Does the test lamp illuminate? | Go to Step 7 | Go to Step 6
6 | Inspect for poor connections at the horn relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 13 | Go to Step 12
7 | Repair the short to ground in the horn relay control circuit. Refer to Circuit Testing and Wiring Repairs . Did you complete the repair? | Go to Step 13 | --
8 | Test the horn switch signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 13 | Go to Step 9
9 | Inspect for poor connections at the harness connector of the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 13 | Go to Step 11
10 | Repair the short to voltage in the horn control circuit. Refer to Circuit Testing and Wiring Repairs . Did you complete the repair? | Go to Step 13 | --
11 | Replace the BCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 13 | --
12 | Replace the horn relay. Did you complete the replacement? | Go to Step 13 | --
13 | Operate the horns. Do the horns operate properly? | System OK | Go to Step 1