Test Description
WARNING: This page is about a different car, the 2007 Pontiac G5 Pursuit, 2007 Pontiac G5, and 2007 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
The numbers below refer to the step numbers on the diagnostic table.
- 4: This step tests for voltage at the battery positive voltage terminal of the horn relay coil.
- 6: This step tests for voltage at the battery positive voltage terminal of the horn relay switch. The HORN fuse supplies power to the battery positive voltage terminal of the horn relay switch.
- 14: The horns need maximum current flow to operate properly. A high resistance, greater than 0.5 ohm, in the horn control circuit or the horn ground circuit could cause operating problems with the horns. Inspect the circuits for faults that would restrict current flow.
Horns Inoperative
| Step | Action | Yes | No |
|---|---|---|---|
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to DIAGNOSTIC SYSTEM CHECK - VEHICLE |
| 2 | Depress the horn switch. Do the horns operate? |
Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3 |
| 3 |
|
Go to Step 11 | Go to Step 4 |
| 4 |
|
Go to Step 5 | Go to Step 15 |
| 5 |
|
Go to Step 6 | Go to Step 12 |
| 6 | 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 7 | Go to Step 16 |
| 7 | Momentarily connect a 15-amp fused jumper wire between the battery positive voltage circuit of the horn relay switch and the horn control circuit. Do the horns operate? |
Go to Step 10 | Go to Step 8 |
| 8 |
|
Go to Step 9 | Go to Step 17 |
| 9 |
|
Go to Step 13 | Go to Step 18 |
| 10 | Inspect for poor connections at 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 22 | Go to Step 19 |
| 11 | Test the horn switch signal for a short to voltage or open. Refer to Circuit Testing
and Wiring Repairs
. Did you find and correct the condition? |
Go to Step 22 | Go to Step 21 |
| 12 | Test the control circuit of the horn relay for a short to voltage or an open. Refer to Circuit Testing
and Wiring Repairs
. Did you find and correct the condition? |
Go to Step 22 | Go to Step 21 |
| 13 |
|
Go to Step 14 | Go to Step 20 |
| 14 | Repair the high resistance in the horn control circuit or the horn ground. A resistance as low as 0.5 ohm could cause operating problems with the horns. Refer to Circuit Testing
and Wiring Repairs
. Did you complete the repair? |
Go to Step 22 | - |
| 15 | Repair the open or high resistance in the battery positive voltage circuit of the horn relay coil. Refer to Circuit Testing
and Wiring Repairs
. Did you complete the repair? |
Go to Step 22 | - |
| 16 | Repair the open or high resistance in the battery positive voltage circuit of the horn relay switch. Refer to Circuit Testing
and Wiring Repairs
. Did you complete the repair? |
Go to Step 22 | - |
| 17 | Repair the open or high resistance in the horn control circuit. Refer to Circuit Testing
and Wiring Repairs
. Did you complete the repair? |
Go to Step 22 | - |
| 18 | Repair the open or high resistance in the horn ground circuit. Refer to Circuit Testing
and Wiring Repairs
. Did you complete the repair? |
Go to Step 22 | - |
| 19 | Replace the horn relay. Refer to Relay Replacement (Attached to Wire Harness)
or Relay Replacement (Within an Electrical Center)
. Did you complete the replacement? |
Go to Step 22 | - |
| 20 | Replace the horn assembly. Refer to Horn Replacement . Did you complete the replacement? |
Go to Step 22 | - |
| 21 | Replace the body control module (BCM). Refer to Control Module References
for replacement, setup, and programming. Did you complete the replacement? |
Go to Step 22 | - |
| 22 | Operate the horns. Do the horns operate properly? |
System OK | Go to Step 1 |