Steering Wheel Controls Inoperative

Steering Wheel Controls Inoperative

Diagnostic Fault Information

Important: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview

Circuit/System Description

The body control module (BCM) supplies voltage to the audio steering wheel control multiple momentary contact switches and monitors the return signal. Each switch is associated to a set resistance value, when pressed a specific voltage drop occurs through a series of resistors unique to that switch. The BCM identifies the selection, then sends a serial data message that is received by the component controlled, activating the feature.

Diagnostic Aids

* This diagnostic is for the audio steering wheel controls.
* Before diagnosis of the steering wheel controls, ensure the primary controls of the associated component are functioning properly.
* Review schematic when testing switch resistance values.
* If a single switch function is inoperative, test the suspect switch. Refer to component testing.

Circuit/System Verification

Ignition ON, observe the BCM data display with the scan tool under Inputs-SWC Bank 1 status. Data displays SW1-SW7 identifying the switch pressed, and Idle when released.

Circuit/System Testing

Caution: Refer to Restraint System Service Precautions.

1. Ignition OFF, disconnect the harness connector at the audio steering wheel control switch.
2. Ignition ON, test for 10-12 volts between the voltage circuit and ground at the switch harness connector.

• If less than 10 volts, test the voltage circuit for a short to ground or an open/high resistance. If circuit test normal, replace the BCM.

3. Test for 0-0.5 volts between the signal circuit and ground at the switch harness connector.

• If greater than 0.5 volts, test the signal circuit for short to voltage. If circuit test normal, replace BCM.

4. Test for 10-12 volts between the voltage circuit and the signal circuit at the switch harness connector.

• If less than 10 volts, test the signal circuit for an open/high resistance. If circuit test normal, replace the BCM.

5. Ignition OFF, disconnect the harness connector at the BCM.
6. Test for infinite resistance between the signal circuit and ground at the harness connector.

• If less than infinite resistance, test the signal circuit for a short to ground. If circuit test normal, replace the BCM.

7. If all circuits test normal, test or replace switch.

Component Testing

Caution: Refer to Restraint System Service Precautions.

1. Ignition OFF, disconnect the harness connector at the audio steering wheel control switch.
2. Test for infinite resistance between the voltage terminal and the signal terminal with the switch in the open position.

• If less than infinite resistance, replace the switch.

3. Test resistance values between the voltage terminal and the signal terminal with the switch closed in each position and verify readings are approximate to what the schematic reads.

• If values do not, replace the switch.

Repair Instructions

Important: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.

* Steering Wheel Control Switch Assembly Replacement
* Control Module References for BCM replacement, setup, and programming Verification Tests