Horn System Buick LeSabre VIII

Fastener Tightening Specifications

Fastener Tightening Specifications

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Horns Schematics

See HORN .

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Diagnostic Starting Point-Horns

Begin the system diagnosis with the 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. 3. The symptoms list in Symptoms will determine the correct diagnostic procedure to use.
3. 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.
4. 6. At this point you have determined all DTCs applicable to the horn system. Refer to «Symptoms-Horns»(/buick/lesabre/viii-2000-2005/remont/body-cab-control-systems/#horn-system__symptoms-horns) for further horn system diagnosis. Any other codes displayed from the listed modules do not apply to horns and should be diagnosed in the applicable section.

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Scan Tool Data List

The Horns Scan Tool Data List contains all of the horns 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.

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Scan Tool Data Definitions

8 Digit GM Part Number: The scan tool displays an 8 digit number which indicates the GM part number of the module.

Battery Voltage: The scan tool displays the current state of the battery in volts.

Calibration ID: The scan tool displays a 4 digit number which indicates the calibration ID number of the module.

Horn Output: The scan tool displays On/Off to indicate the current state of the horn as commanded by the dash integration module (DIM).

Julian Date of Build: The scan tool displays a 3 digit number which indicates the Julian date of build of the module.

PROM ID: The scan tool displays a 4 digit number that identifies the PROM.

Year Module Built: The scan tool displays a 4 digit number which indicates the year the module was built.

Symptoms-Horns

Note. 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.
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 (71 lb ft).

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS .

Symptom List

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

1. «Horns Always On»(/buick/lesabre/viii-2000-2005/remont/body-cab-control-systems/#horn-system)
2. «Horns Inoperative»(/buick/lesabre/viii-2000-2005/remont/body-cab-control-systems/#horn-system)
3. «Horns - Poor Tone»(/buick/lesabre/viii-2000-2005/remont/body-cab-control-systems/#horn-system)

The number(s) below refer to the step number(s) 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 inflatable restraint steering wheel module coil and the horn switch. The horn switch is part of the inflatable restraint steering wheel module. The inflatable restraint steering wheel module coil and the horn switch must be tested for a short to ground when testing the relay control circuit.

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

1. 4. Verifies that the Dash Integration Module (DIM) 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. 15. 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. Check the circuits for faults that would restrict current flow.
5. 17. The horn relay control circuit includes the inflatable restraint steering wheel module coil and the horn switch. The horn switch is part of the inflatable restraint steering wheel module. The inflatable restraint steering wheel module coil and the horn switch must be tested for a high resistance, an open or a short to voltage when testing the relay control circuit.

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1. Remove the left front fascia extension. Refer to «FASCIA EXTENSION REPLACEMENT - FRONT»(/buick/lesabre/viii-2000-2005/remont/exterior-body-panels/#bumper-system) .
2. Disconnect the electrical connector from the horn assembly.
3. Remove the bolt securing the horn assembly to the left front frame rail.
4. Remove the horn assembly.

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1. Position the horn assembly to the left front frame rail.
2. Install the horn assembly bolt. Tighten: Tighten the bolt to 15 N.m (11 lb ft)
3. Connect the electrical connector to the horn assembly.
4. Install the left front fascia extension. Refer to «FASCIA EXTENSION REPLACEMENT - FRONT»(/buick/lesabre/viii-2000-2005/remont/exterior-body-panels/#bumper-system) in Body Front End.

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1. Open the hood.
2. Remove the cover from the underhood fuse block.
3. Remove the horn relay (1) from the underhood fuse block.

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1. Install the horn relay (1) to the underhood fuse block.
2. Install the cover to the underhood fuse block.
3. Close the hood.

System Description

The horn system consists of the following components

1. The horn fuse
2. The horn relay
3. The horn slip ring
4. The inflatable restraint steering wheel coil
5. The horn switch (The horn switch is part of the inflatable restraint steering wheel module.)
6. The horns
7. The Dash Integration Module (DIM)

System Operation

The vehicle horns are activated under the following conditions

1. The horn switch is depressed.
2. The Dash Integration Module (DIM) commands the horns on. The DIM 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 CONTENT THEFT DETERRENT (CTD) DESCRIPTION AND OPERATION in THEFT DETERRENT . When the panic button is depressed on the remote control door lock transmitter. For further information refer to KEYLESS ENTRY SYSTEM DESCRIPTION AND OPERATION in KEYLESS ENTRY . When the OnStar® system is used to sound the horns (if equipped). For further information refer to ONSTAR DESCRIPTION AND OPERATION in CELLULAR COMMUNICATION . 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 in KEYLESS ENTRY .

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 DIM 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.

See also:
• TESTING FOR INTERMITTENT AND POOR CONNECTIONS
• FASCIA EXTENSION REPLACEMENT - FRONT
• Diagnostic System Check-Horns
• Symptoms-Horns