For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Horn Schematics DEFINITION: Horns Inoperative at all times
1 | Did you review the Horn System Description and Operation and perform the necessary inspections? | Go to Step 2 | Go to Horns System Description and Operation
2 |

1. Remove the horn relay.
2. Using a test lamp, test for battery positive voltage at the switch side of the relay battery positive voltage circuit.

Is voltage present?

Go to Step 3

Go to Step 4

3 | Using a test lamp, test for battery positive voltage at the coil side of the relay battery positive voltage circuit. Is voltage present? | Go to Step 5 | Go to Step 4
4 | Repair the open or short in the battery positive circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems Did you find and correct the condition? | Go to Step 18 | --
5 |

1. With the horn switch depressed.
2. Using a test lamp connected to battery positive voltage. Test the horn signal circuit at the relay for ground. Refer to Circuit Testing in Wiring Systems.

Is ground present?

Go to Step 7

Go to Step 6

6 |

1. With the horn switch depressed.
2. Using a test lamp connected to battery positive voltage. Test the horn signal circuit at the switch for ground. Refer to Circuit Testing in Wiring Systems

Is ground present?

Go to Step 7

Go to Step 12

7 |

1. Disconnect the horn connector.
2. With the horn switch depressed, Use a test lamp connected to a good ground, Test the horn voltage feed circuit at the horn connector for battery positive voltage.

Is voltage present?

Go to Step 9

Go to Step 15

8 | Repair the open in the horn switch signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and complete the repair? | Go to Step 18 | --
9 | With the horn connector still disconnected, Test the ground circuit for ground. Refer to Circuit Testing in Wiring Systems. Is there ground present? | Go to Step 10 | Go to Step 11
10 | Replace the horn. Refer to Horn Replacement . Did you complete the replacement? | Go to Step 18 | --
11 | Repair the open in the horn ground circuit. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 18 | --
12 | Using a test lamp connected to battery positive voltage, test the horn switch ground circuit for ground. Refer to Wiring Repairs in Wiring Systems. Is ground present? | Go to Step 13 | Go to Step 14
13 | Replace the horn switch. Did you complete the replacement? | Go to Step 18 | --
14 | Repair the open in the horn switch ground circuit. Refer to Wiring Repairs in Wiring Systems. Did you correct the condition? | Go to Step 18 | --
15 | With the horn switch depressed, Test the horn feed circuit at the relay for battery positive voltage. Refer to Circuit Testing in Wiring Systems Is voltage present? | Go to Step 16 | Go to Step 17
16 | Repair the open in the horn supply voltage circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 18 | --
17 | Replace the horn relay. Did you complete the replacement? | Go to Step 18 | --
18 | Operate the system in order to verify repair. Did you correct the condition? | System OK | Go to Step 2