Horn System Buick Rendezvous I

Fastener Tightening Specifications

Fastener Tightening Specifications

Horns Schematic Icons

Horns Schematic Icons Icon Icon Definition CAUTION: When performing service on or near the SIR components or the SIR wiring, the SIR system must be disabled. Refer to SIR Disabling and Enabling Zones. Failure to observe the correct procedure could cause deployment of the SIR components, personal injury, or unnecessary SIR system repairs

Scheme 1

Scheme 2

Horns Connector End Views

Horn Connector End - Left (Low Note) Connector Part Information 12052644 2-Way F Metri-Pack 150 Series Sealed (GRY) Pin Wire Color Circuit No. Function A BLK 1350 Ground B DK GRN 29 Horn Control

Horn Connector End - Right (High Note) Connector Part Information 12052644 2-Way F Metri-Pack 150 Series Sealed (GRY) Pin Wire Color Circuit No. Function A BLK 1250 Ground B DK GRN 29 Horn Control

Diagnostic Starting Point - Horns

Begin the system diagnosis with Diagnostic System Check - Horns . The Diagnostic System Check will provide the following information

1. The identification of the control module(s) which command the system.
2. The ability of the control module(s) to communicate through the serial data circuit.
3. The identification of any stored diagnostic trouble codes (DTCs) and their status.

The use of the Diagnostic System Check will identify the correct procedure for diagnosing the system and where the procedure is located.

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

1. 2: Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.
2. 4: The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.

Diagnostic System Check - Horns

Scan Tool Output Controls

Scan Tool Output Controls

Scan Tool Data List

The Horns Scan Tool Data List contains all of the horn related parameters that are available on the scan tool. The parameters in the list are arranged in alphabetical order. The column, "Data List," indicates the location of the parameter within the scan tool menu selections. Use the Horns Scan Tool Data List as directed by a diagnostic table or in order to supplement the diagnostic procedures. Begin all of the diagnostic procedures with Diagnostic System Check - Horns .

Use the Scan Tool Data List only after the following is determined

1. There is no published DTC procedure nor published symptom procedure for the customer concern.
2. The DTC or symptom diagnostic procedure indicated by the diagnostic system check does not resolve the customer concern.

The Typical Data Values are obtained from a properly operating vehicle under the conditions specified in the first row of the Scan Tool Data List table. Comparison of the parameter values from the suspect vehicle with the Typical Data Values may reveal the source of the customer concern.

Scan Tool Data List

Diagnostic Trouble Code (DTC) List

Diagnostic Trouble Code (DTC) List

Circuit Description

The vehicle horn is activated whenever ground is applied to the horn relay coil through the horn relay control circuit. Ground may be applied by either of the following

1. The body control module (BCM)
2. The horn switch

Conditions for Running the DTC

The BCM commands the horn relay to energize.

Conditions for Setting the DTC

The BCM detects a short to ground in the horn relay control circuit for approximately 300 milliseconds.

Action Taken When the DTC Sets

1. The horn will remain on at all times.
2. The BCM stores DTC B2752 in memory.

Conditions for Clearing the DTC

1. A current DTC will clear when the fault is no longer present and the ignition switch is cycled.
2. A history DTC will clear after 100 consecutive ignition cycles without a fault present.
3. A scan tool may be used to clear history and current DTCs.

Diagnostic Aids

1. Always begin diagnosis with the first DTC listed on the scan tool.
2. The scan tool must display DTC B2752 as a current code before performing these diagnostics.
3. Inspect for a sticking horn pad and or switch.
4. Perform a visual inspection for loose or poor connections at all related components.
5. Refer to «Testing for Intermittent Conditions and Poor Connections»(/buick/rendezvous/i-2001-2007/remont/body-electrical/#wiring-systems-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor) in Wiring Systems.

The numbers below refer to the step numbers on the diagnostic table.

1. 2: Listen for an audible click when the horn relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
2. 3: Tests for voltage at the coil side of the horn relay. The HORN fuse supplies power to the coil side of the horn relay.
3. 4: Verifies that the body control module (BCM) is providing ground to the horn relay.
4. 5: Tests if ground is constantly being applied to the horn relay.

DTC B2752

Symptoms - Horns

1. Perform «Diagnostic System Check - Horns»(/buick/rendezvous/i-2001-2007/remont/horns/#horn-system) before using the symptom tables in order to verify that all of the following are true: There are no DTCs set. The control module(s) can communicate via the serial data link.
2. Review the system operation in order to familiarize yourself with the system functions. Refer to «Horns System Description and Operation»(/buick/rendezvous/i-2001-2007/remont/horns/#horn-system) .

Visual/Physical Inspection

1. Inspect for aftermarket devices which could affect the operation of the horn system. Refer to «Checking Aftermarket Accessories»(/buick/rendezvous/i-2001-2007/remont/body-electrical/#wiring-systems-diagnostic-information-and-procedures__checking-aftermarket-accessories) in Wiring Systems.
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 in Wiring Systems.

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

1. «Horns Always On»(/buick/rendezvous/i-2001-2007/remont/horns/#horn-system)
2. «Horns Inoperative»(/buick/rendezvous/i-2001-2007/remont/horns/#horn-system)
3. «Horns Inoperative - One Horn»(/buick/rendezvous/i-2001-2007/remont/horns/#horn-system)
4. «Horns - Poor Tone»(/buick/rendezvous/i-2001-2007/remont/horns/#horn-system__horns-poor-tone)

The numbers below refer to the step numbers on the diagnostic table.

1. 4: Tests if ground is constantly being applied to the horn relay.
2. 5: The horn relay control circuit includes the horn switch. The horn switch is part of the inflatable restraint steering wheel module. The horn switch must be tested for a short to ground when testing the relay control circuit.

Horns Always On

The numbers below refer to the step numbers on the diagnostic table.

1. 4: Verifies that the body control module (BCM) is providing ground to the horn relay.
2. 5: Tests for voltage at the battery positive voltage terminal of the horn relay coil.
3. 7: 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.
4. 13: The horn needs maximum current flow to operate properly. A high resistance, greater than 0.5ohms, in the horn control circuit or the horn ground circuit could cause operating problems with the horn. Inspect the circuits for faults that would restrict current flow.
5. 15: The horn relay control circuit includes the horn switch. The horn switch is part of the inflatable restraint steering wheel module. The horn switch must be tested for a high resistance, an open or a short to voltage when testing the relay control circuit.

Horns Inoperative

The number(s) below refer to the step number(s) on the diagnostic table.

1. 9: The horns need maximum current flow to operate properly. A high resistance (greater than 0.5ohms) 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 - One Horn

Horns - Poor Tone

Horns - Poor Tone

Removal Procedure

1. Remove the right and/or left headlamp. Refer to «Headlamp Assembly or Headlamp Bulb Replacement (Aztek)»(/buick/rendezvous/i-2001-2007/remont/exterior-lights/#lighting-systems) or «Headlamp Assembly or Headlamp Bulb Replacement (Rendezvous)»(/buick/rendezvous/i-2001-2007/remont/exterior-lights/#lighting-systems) in Lighting Systems.
2. Disconnect the horn electrical connector.
3. Remove the horn bracket bolt.
4. Remove the horn from the front bumper impact bar.

Installation Procedure

1. Position the horn to the front bumper impact bar; position the horn anti-rotation tab onto the tab on the front bumper impact bar.
2. Install the horn bracket bolt. Tighten: Tighten the bolt to 10 N.m (89 lb in).
3. Connect the horn electrical connector.
4. Install the right and/or left headlamp. Refer to «Headlamp Assembly or Headlamp Bulb Replacement (Aztek)»(/buick/rendezvous/i-2001-2007/remont/exterior-lights/#lighting-systems) or «Headlamp Assembly or Headlamp Bulb Replacement (Rendezvous)»(/buick/rendezvous/i-2001-2007/remont/exterior-lights/#lighting-systems) in Lighting Systems.

System Description

The horn system consists of the following components

1. The horn fuse
2. The horn relay
3. The horn switch, the horn switch is part of the inflatable restraint steering wheel module
4. The horn, vehicle may be equipped with a one or two horn system
5. The body control module (BCM)

System Operation

The vehicle horn system is activated under the following conditions

1. The horn switch is depressed.
2. The body control module (BCM) commands the horn on. The BCM commands the horn on under any of the following conditions: When the content theft deterrent system detects a vehicle intrusion. For further information refer to «Content Theft Deterrent (CTD) Description and Operation»(/buick/rendezvous/i-2001-2007/remont/door-locks-anti-theft-systems/#theft-deterrent-system__content-theft-deterrent-ctd-description-and) in Theft Deterrent. When the panic button is depressed on the remote control door lock transmitter. For further information refer to «Content Theft Deterrent (CTD) Description and Operation»(/buick/rendezvous/i-2001-2007/remont/door-locks-anti-theft-systems/#theft-deterrent-system__content-theft-deterrent-ctd-description-and) in Theft Deterrent. 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/rendezvous/i-2001-2007/remont/door-locks-anti-theft-systems/#keyless-entry-system) in Keyless Entry. When the OnStar® system is used to sound the horn. For further information refer to «OnStar Description and Operation»(/buick/rendezvous/i-2001-2007/remont/entertainment-systems/#cellular-communication-system__onstar-description-and-operation) in Cellular Communication.

Circuit Operation

Battery positive voltage is applied at all times to the horn relay coil and the horn relay switch. Pressing the horn switch 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 horn through the horn control circuit. The horn sounds as long as ground is applied to the horn relay control circuit.

See also:
• Scan Tool Does Not Power Up
• Diagnostic Trouble Code (DTC) List
• Diagnostic Trouble Code (DTC) List
• Testing for Intermittent Conditions and Poor Connections
• Circuit Testing
• Wiring Repairs
• Connector Repairs
• Body Control Module Replacement
• Checking Aftermarket Accessories
• Inflatable Restraint Steering Wheel Module Replacement (Aztek)
• Headlamp Assembly or Headlamp Bulb Replacement (Aztek)
• Content Theft Deterrent (CTD) Description and Operation
• Keyless Entry System Description and Operation
• OnStar Description and Operation
• Diagnostic System Check - Horns
• Symptoms - Horns
• Diagnostic Trouble Code (DTC) List
• Horns - Poor Tone
• Fastener Tightening Specifications