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Horn System Buick Enclave I

Horns 3 illustrations ~2324 words

Fastener Tightening Specifications

ApplicationSpecification
MetricEnglish
Cruise Control Switch Bolt2.5 N.m22 lb in
Horn Bracket Bolt9 N.m80 lb in
Radio Control Switch Bolt2.5 N.m22 lb in

Fastener Tightening Specifications

Scheme 1

Scheme 1: Horns
Scheme 1: Horns

Diagnostic Code Index

DTCDescription
DTC B2750DTC B2750 00 Horn Relay Coil Circuit

DIAGNOSTIC CODE INDEX

Diagnostic Instructions

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information

CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Horn Relay B+22
Horn Relay ControlB2750 00B2750 00B2750 00
Horn Control221
Horn Switch Ground22
Horn Ground22
1. Horn Always On 2. Horn Inoperative

Circuit/System Description

The body control module (BCM) controls the horn relay by grounding the control circuit of the horn relay coil energizing the relay. When the horn relay is energized, the horn relay contacts close applying voltage through the horn fuse and the horn control circuit to the horns.

Conditions for Running the DTC

When the horn output is actively being requested by the BCM.

Conditions for Setting the DTC

The BCM detects a short to ground, open, or short to voltage in the horn relay control circuit for approximately 125 milliseconds.

Action Taken When the DTC Sets

The BCM disables the output to the horn relay until the next ignition cycle.

Conditions for Clearing the DTC

  1. The DTC clears when the fault is no longer detected.
  2. The current DTC will become history when the request for the output is removed.
  3. The history DTC will clear after 50 consecutive fault-free ignition cycles have occurred.

Reference Information

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

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.

Circuit/System Testing

  1. Ignition OFF, disconnect the HORN relay.
  2. Ignition ON, verify 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 fuse is open, test the control circuit terminal 87 for a short to ground. If all circuits test normal, test or replace the HORN relay.
  3. Connect a test lamp between the control circuit terminal 86 and the B+ circuit terminal 85.
  4. Command the horns 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 OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM
  5. If all circuits test normal, test or replace the HORN relay.

Component Testing

  1. Ignition OFF, disconnect the horn relay.
  2. Test for 60-180 ohms between terminals 85 and 86. If not within the specified range, replace the relay.
  3. Test for infinite resistance between the following terminals: 30 and 86 30 and 87 30 and 85 85 and 87 If not the specified value, replace the relay.
  4. Install a 30-amp fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87. If greater than the specified range, replace the relay.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Relay Replacement (Within an Electrical Center)»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions__relay-replacement-within-an-electrical-center) , «Relay Replacement (Attached to Wire Harness)»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Control Module References»(/buick/enclave/i-2007-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup and programming

Symptoms - Horns

IMPORTANTThe following steps must be completed before using the symptom tables: Perform Diagnostic System Check - Vehicle , before using the symptom tables in order to verify that all of the following are true: There are no DTCs set The control modules can communicate via the serial data link Review the system operation in order to familiarize yourself with the system functions. Refer to Horns System Description and Operation .

Visual/Physical Inspection

  1. Inspect for aftermarket devices which could affect the operation of the horn system. Refer to «Checking Aftermarket Accessories»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__checking-aftermarket-accessories) .
  2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
  3. Perform the following if a horn buzzes or has a harsh tone. Inspect for debris in the joint where the horn fastens to the vehicle. Test the torque of the horn mounting hardware. The horn mounting hardware should be tightened to a torque of 10 N.m (7 lb ft).

Intermittent

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

Symptom List

Refer to a symptom diagnostic procedure Horns Malfunction in order to diagnose the symptom.

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Horn Relay B+22
Horn Relay Control12B2750 00
Horn Control221
Horn Switch Ground2
Horn Ground2
1. Horn Always On 2. Horn Inoperative

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

OnStar® RemoteLink™ applications or "apps" downloads are available to owners of certain mobile devices. Unwanted or inadvertent horn activations have been associated with these applications to which the customer may be unaware. Contact the GM Technical Assistance Center regarding information on a remedy for this situation.

A short to ground in the horn relay control circuit or a short to voltage in the horn control circuit will cause the horn to sound continuously until the horn overheats and become inoperative.

Rotate the steering wheel while pressing the horn pad to identify intermittent and poor connections within the steering column.

If diagnosing a Horn- Poor Tone condition, inspect the following

  1. Debris or water in the horn assembly.
  2. Proper horn mounting hardware torque. Refer to «Fastener Tightening Specifications»(/buick/enclave/i-2007-2013/remont/horns/#horn-system__fastener-tightening-specifications) .
  3. Debris in the joint where the horns attach to the vehicle.
  4. Debris in direct contact with the horn
  5. Vehicle components vibrating while the horn is sounding

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

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. If the sound emitted from the horns are not clear and even, refer to Horn - Poor Tone.
  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.

Horn Malfunction

  1. Ignition OFF, disconnect the X2 harness connector at the horn switch.
  2. Ignition ON, test for less than 1 ohms 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 15 A 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 ohms 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.

Horn Test

  1. Ignition OFF, disconnect the harness connector at the appropriate horn.
  2. Install a 15 A fused jumper wire between the control terminal B and 12 V. Install a jumper wire between the ground terminal A and ground. Verify the horn emits a clear and even tone. If the sound emitted is not clear and even, replace the horn.

Relay Test

  1. Ignition OFF, disconnect the HORN relay.
  2. Test for 60-180 ohms between terminals 85 and 86. If not within the specified range, replace the relay.
  3. Test for infinite resistance between the following terminals: 30 and 86 30 and 87 30 and 85 85 and 87 If not the specified value, replace the relay.
  4. Install a 30 A fused jumper wire between relay terminal 85 and 12 V. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87. If greater than the specified range, replace the relay.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Relay Replacement (Within an Electrical Center)»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions__relay-replacement-within-an-electrical-center) , «Relay Replacement (Attached to Wire Harness)»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Horn Replacement»(/buick/enclave/i-2007-2013/remont/horns/#horn-system)
  3. «Steering Wheel Horn Switch Replacement»(/buick/enclave/i-2007-2013/remont/horns/#horn-system)
  4. «Control Module References»(/buick/enclave/i-2007-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, programming and setup

Scheme 2

Scheme 2: Horn Replacement
Scheme 2: Horn Replacement
CalloutComponent Name
Preliminary Procedure Remove the front wheelhouse liner (front). Refer to Front Wheelhouse Front Liner Replacement (Enclave - Acadia) , Front Wheelhouse Front Liner Replacement (Traverse) .
1Horn Bolt CAUTION: Refer to Fastener Caution . Tighten 9 N.m (80 lb in)
2Horn Procedure Disconnect the electrical connector.
CAUTION
Refer to Fastener Caution .

Horn Replacement

Scheme 3

Scheme 3: Steering Wheel Horn Switch Replacement
Scheme 3: Steering Wheel Horn Switch Replacement
CalloutComponent Name
Preliminary Procedure Remove the inflatable restraint steering wheel module. Refer to Steering Wheel Inflatable Restraint Module Replacement .
1Steering Wheel Spoke Cover (Qty: 2) TIP: Use gentle pressure to disengage the steering wheel spoke covers from the steering wheel.
2Radio Control Switch Bolt (Qty: 2) CAUTION: Refer to Fastener Caution . Tighten 2.5 N.m (22 lb in)
3Radio Control Switch Procedure Disconnect any electrical connectors as needed.
4Cruise Control Switch Bolt (Qty: 2) Tighten 2.5 N.m (22 lb in)
5Cruise Control Switch Procedure Disconnect any electrical connectors as needed.
6Horn Switch Procedure Disconnect any electrical connectors as needed. TIP: Use gentle pressure to disengage the horn switch from the steering wheel.
CAUTION
Refer to Fastener Caution .

Steering Wheel Horn Switch Replacement

System Description

The horn system consists of the following components

  1. HORN fuse
  2. Horn relay
  3. Horn switch
  4. Horn assembly
  5. Body control module (BCM)

System Operation

The vehicle horn system is activated under the following conditions

  1. When the horn switch is depressed
  2. The BCM commands the horns ON under any of the following conditions: When the content theft deterrent system detects a vehicle intrusion-For further information refer to «Theft Systems Description and Operation»(/buick/enclave/i-2007-2013/remont/door-locks-anti-theft-systems/#theft-deterrent-system__theft-systems-description-and-operation) . When the panic button is depressed on the remote control door lock transmitter-For further information refer to «Keyless Entry System Description and Operation»(/buick/enclave/i-2007-2013/remont/door-locks-anti-theft-systems/#keyless-entry-system-and-remote-functions__keyless-entry-system-description-and-operation) . When the keyless entry system is used to lock the vehicle, a horn chirp may sound to notify the driver that the vehicle has been locked. The notification feature may be enabled or disabled through personalization. For further information refer to «Keyless Entry System Description and Operation»(/buick/enclave/i-2007-2013/remont/door-locks-anti-theft-systems/#keyless-entry-system-and-remote-functions__keyless-entry-system-description-and-operation) . When the OnStar® system is used to sound the horns if equipped-For further information, refer to «OnStar Description and Operation»(/buick/enclave/i-2007-2013/remont/entertainment-systems/#cellular-system-entertainment-system-and-navigation-system__onstar-description-and-operation) .

Circuit Operation

Battery positive voltage is applied at all times to the horn relay coil and the horn relay switch. Pressing either of the horn switches applies ground to the horn relay control circuit. The BCM may also apply ground to the horn relay control circuit as described above. When the horn relay control circuit is grounded, the horn relay is energized and battery positive voltage is applied to the horns through the horn control circuit. The horns sound as long as ground is applied to the horn relay control circuit.