Horn System: Other GMC Acadia I

Reference Information

Schematic Reference

Horn Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Horns System Description and Operation

Electrical Information Reference

1. «Circuit Testing»(ref-365275-S00040570812010070600000)
2. «Connector Repairs»(ref-365275-S19060558252010070600000)
3. «Testing for Intermittent Conditions and Poor Connections»(ref-365275-S00287822652010070600000)
4. «Wiring Repairs»(ref-365275-S21384576672010070600000)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Command the horns ON and OFF with the scan tool. The horns should turn ON and OFF when changing between the commanded states.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Relay Replacement (Attached to Wire Harness)»(ref-365277-S15413989202010070600000)
2. «Control Module References»(ref-365276-S01454229382010070600000) for BCM replacement, setup and programming

Symptoms - Horns

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections .

Schematic Reference

Horn Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Horns System Description and Operation

Electrical Information Reference

1. «Circuit Testing»(ref-365275-S00040570812010070600000)
2. «Connector Repairs»(ref-365275-S19060558252010070600000)
3. «Testing for Intermittent Conditions and Poor Connections»(ref-365275-S00287822652010070600000)
4. «Wiring Repairs»(ref-365275-S21384576672010070600000)

Scan Tool Reference

Control Module References for scan tool information

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 Malfunction»(ref-365279-S31402099712010072300000) . If the sound emitted from the horns are not clear and even, refer to «Horn - Poor Tone»(ref-365279-S31202129932010072300000) .
2. Command the Horn ON and OFF with the scan tool. The horns should turn ON and OFF when changing between the commanded states. If the horns do not turn ON and OFF when changing between the commanded states, refer to «Command Malfunction»(ref-365279-S28265910862010072300000) .

Horn Malfunction

1. Ignition OFF, disconnect the X2 harness connector at the horn switch.
2. Ignition ON, test for less than 1 ohm between the ground circuit terminal 1 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition OFF, connect the harness connector at the horn switch and disconnect the HORN relay.
4. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
5. Verify that a test lamp illuminates between the B+ circuit terminal 85 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal 87 for a short to ground. If the circuit tests normal, test or replace the HORN relay.
6. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
7. Ignition OFF, disconnect the harness connector at the appropriate horn.
8. Test for less than 5 ohms between the ground circuit terminal A and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
9. Connect the harness connector at the horn.
10. Ignition ON, connect a 15A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the horns are activated. If the horns do not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the horns.
11. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
12. Press and release the steering wheel horn pad. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, inspect for a sticking horn switch. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, inspect for an open horn switch.
13. If all circuits test normal, test or replace the HORN relay.

Horn - Poor Tone

1. Ignition OFF, disconnect the harness connector at the appropriate horn.
2. Test for less than 5 ohms between the horn ground circuit terminal A and ground. If greater than the specified range, test the ground circuit for a high resistance.
3. Disconnect the HORN relay.
4. Test for less than 1 ohm between the control circuit terminal 87 and the control circuit terminal B at the horn. If greater than the specified range, test the control circuit for high resistance.
5. If all circuits test normal, test or replace the horn.

Command Malfunction

1. Ignition OFF, disconnect the HORN relay.
2. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
3. Ignition ON, command the Horn ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. If the test lamp is always OFF, test circuit the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Relay Replacement (Attached to Wire Harness)»(ref-365277-S15413989202010070600000)
2. «Horn Replacement»(ref-365279-S37641191922010070600000)
3. «Steering Wheel Horn Switch Replacement»(ref-365279-S10347862202010070600000)
4. «Control Module References»(ref-365276-S01454229382010070600000) for BCM replacement, setup, and programming

Scheme 2

Scheme 3