For 1990-2009 cars

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. If the horn relay continues grounding.

2. The horn relay control circuit includes horn slip ring and horn switch. While testing the relay control circuit, test if the horn slip ring and button is short to ground.

Step | Action | Yes | No
--- | --- | --- | ---
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 |

1. Install the scan tool.
2. Turn ON the ignition, with the engine OFF.
3. Use a scan tool to command the DIM horn output ON/OFF.

Is the horn always ON?

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections

3 |

1. Turn OFF the ignition.
2. Disconnect the horn relay.

Is the horn always ON?

Go to Step 8

Go to Step 4

4 | Connect a test lamp at the battery positive voltage circuit of the horn relay coil and the control circuit of the horn relay. Does the test light illuminate? | Go to Step 5 | Go to Step 6
5 | Test if the horn relay control circuit is short to ground. The horn relay control circuit includes horn slip ring and horn switch. Refer to Circuit Testing and Wiring Repairs. Did you find and correct the condition? | Go to Step 11 | Go to Step 7
6 | Inspect for poor connection of 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 11 | Go to Step 9
7 | Check for poor connections at the harness connector of the DIM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs. Did you find and correct the condition? | Go to Step 11 | Go to Step 10
8 | Repair the short to voltage in the horn relay control circuit. Refer to Circuit Testing and Wiring Repairs. Did you find and correct the condition? | Go to Step 11 | --
9 | Replace the horn relay. Did you complete the replacement? | Go to Step 11 | --
10 | Replace the DIM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 11 | --
11 | Operate the horn. Is the horn working normally? | System OK | Go to Step 1