Sky L4-2.0L Turbo (2008)
Battery positive voltage is applied at all times to the horn relay coil and the horn relay switch. Pressing the horn switch applies ground through the switch
contacts and the horn relay control circuit to the coil side of the relay, energizing the relay. Battery voltage is then applied through the switch side of the
relay, the horn fuse, and the horn control circuit to the horns. The body control module (BCM) may also apply ground to the horn relay control circuit as
described above. The horns sound as long as ground is applied to the horn relay control circuit.
Diagnostic Aids
If diagnosing a Horn - Poor Tone condition, inspect the following:
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Debris or water in the horn assembly
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Proper horn mounting hardware torque-Refer to Fastener Tightening Specifications (See: Specifications) .
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Debris in the joint where the horns attach to the vehicle
Reference Information
Schematic Reference
Horn Schematics (See: Diagrams/Electrical Diagrams)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Horns System Description and Operation (See: Description and Operation)
Electrical Information Reference
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Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics)
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Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics)
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Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics)
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Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for Scan Tool Information
Circuit/System Verification
1. Ignition ON, press and release the steering wheel horn pad. The horns should sound and emit a clear and even tone only when the horn pad is
pressed.
‹› If the horns do not sound when the horn pad is pressed or continues sounding after the horn pad is released, refer to Horn Switch Circuit Test.
‹› If the sound emitted from the horns are not clear and even, refer to Horn - Poor Tone.
2. Command the horns ON and OFF with the scan tool. The horns should turn ON and OFF when changing between the commanded states.
‹› If the horn does not turn ON and OFF when changing between the commanded states, refer to Horn Circuit Test.
Circuit/System Testing
Horn Switch Circuit Test
1. Disconnect the HORN relay.
2. Ignition ON, verify that a test lamp does not illuminate between the relay controlled output circuit and ground.
‹› If the test lamp illuminates, test the relay controlled output circuit for a short to voltage.
3. Verify that a test lamp illuminates between the relay coil B+ circuit and ground.
‹› If the test lamp does not illuminate, test the relay coil B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and
the HORN fuse is open, test the relay controlled output circuit for a short to ground. If the circuit tests normal, test or replace the HORN relay.
4. Verify that a test lamp illuminates between the relay switch B+ circuit and ground.
‹› If the test lamp does not illuminate, test the relay switch B+ circuit for an open/high resistance.
5. Disconnect the harness connector at the horn.
6. Test for less than 1.0 ohm between the horn ground circuit terminal A and ground.
