For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
DEFINITION: The diagnostic procedure is used to diagnose the one horn trouble condition in several horn systems.
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 | Press the horn switch. Does the horn sound harshly or abuzzly? | Go to Step 3 | Go to Symptoms - Horns
3 |

1. Test the torque of the horn mounting hardware. Refer to Horn Replacement .
2. Inspect for debris in the joint where the horn fastens to the vehicle.

Did you find and correct the condition?

Go to Step 7

Go to Step 4

4 | Perform the following steps to each horn:

1. Disconnect the horn connector.
2. Connect a 15A fused jumper between the battery positive terminal and the horn control terminal.
3. Connect another jumper between the battery negative terminal and the horn ground terminal.

Does the horn sound harshly or abuzzly?

Go to Step 6

Go to Step 5

5 | Repair the high resistance in the horn control circuit and horn ground circuit. Refer to Circuit Testing and Wiring Repairs . Is the repair complete? | Go to Step 7 | --
6 | Replace the horn. Refer to Horn Replacement . Did you complete the replacement? | Go to Step 7 | --
7 | Operate the horn. Is the horn working normally? | System OK | Go to Step 1