GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Horn Schematics

1

Did you review the Horns Description and Operation and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Horns

2

Verify that the horns are always on.

Does the system operate normally?

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

Go to Step 3

3

Disconnect the horn relay.

Is the horn on at all times?

Go to Step 7

Go to Step 4

4

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 6

Go to Step 5

5

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 9

Go to Step 8

6

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

Repair the short to ground in the horn relay control circuit. (The horn relay control circuit includes the inflatable restraint steering wheel module coil and the horn switch.) Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 9

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7

Repair the short to voltage in the horn control circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 9

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8

Replace the horn relay.

Did you complete the replacement?

Go to Step 9

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9

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3