Did you review the Horns operation and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Horns

Depress the horn switch.

Does the horn operate?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

1. Disconnect the horn relay.
2. Connect a test lamp between the battery positive voltage circuit of the horn relay coil and a good ground.

Does the test lamp illuminate?

Go to Step 4

Go to Step 13

1. Connect a test lamp between the battery positive voltage circuit of the horn relay coil and the horn relay control circuit.
2. Depress and hold the horn switch.

Does the test lamp illuminate?

Go to Step 5

Go to Step 14

5

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 6

Go to Step 15

Momentarily connect a 15 amp fused jumper wire between the battery positive voltage circuit of the horn relay switch and the horn control circuit.

Does the horn operate?

Go to Step 11

Go to Step 7

1. Reconnect the horn relay.
2. Disconnect the horn connector.
3. Connect a test lamp between the horn control circuit and a good ground.
4. Depress and hold the horn switch.

Does the test lamp illuminate?

Go to Step 8

Go to Step 16

1. Connect a test lamp between the horn control circuit and the horn ground circuit.
2. Depress and hold the horn switch.

Does the test lamp illuminate?

Go to Step 9

Go to Step 17

Inspect for poor connections at the horn. 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 20

Go to Step 10

1. Connect a 15 amp fused jumper wire between the positive battery terminal and the control terminal of the horn.
2. Connect another jumper wire between the negative battery terminal and the ground terminal of the horn.

Does the horn operate?

Go to Step 12

Go to Step 19

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 20

Go to Step 18

12

Repair the high resistance in the horn control circuit or the horn ground circuit. A resistance as low as 0.5 ohms 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 20

--

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 20

--

14

To disable the SIR system refer to Disabling the SIR System in SIR.

Repair the open or short to voltage in the horn relay control circuit. The horn relay control circuit includes the horn slip ring and the horn switches. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 20

--

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 20

--

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 20

--

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 20

--

Replace the horn relay.

Did you complete the replacement?

Go to Step 20

--

Replace the horn. Refer to Horn Replacement .

Did you complete the replacement?

Go to Step 20

--

Operate the horn.

Does the horn operate properly?

System OK

Go to Step 1