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.

Before diagnosis of the steering wheel controls, ensure the primary controls of the associated component are functioning properly.

Schematic Reference

Steering Wheel Secondary/Configurable Control Schematics

Connector End View Reference

Description and Operation

Steering Wheel Controls Description and Operation

Electrical Information Reference

Ignition ON, observe the scan tool steering wheel control (SWC) Bank 1 status. While pressing and releasing the switches. The reading should be SW1-SW7 identifying the switch pressed, and Idle when released.

Caution: Refer to SIR Caution in the Preface section.

Important: It is recommended that Component Testing is performed before Circuit Testing when diagnosing steering wheel controls.

1. Ignition OFF, disconnect the harness connector at the left steering wheel control switch.
2. Ignition ON, test for ignition voltage between the ignition circuit terminal 1 and ground.

⇒	If less than the specified value, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

3. Test for 0 volt between the signal circuit terminal 4 and ground.

⇒	If greater than the specified value, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM.

4. Test for ignition voltage between the ignition circuit terminal 1 and the signal circuit terminal 4.

⇒	If less than the specified value, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the BCM.

5. Install a 3A fused jumper wire at the ignition circuit terminal 1 and the signal circuit terminal 5.
6. Disconnect the harness connector at the right steering wheel control switch.
7. Test for ignition voltage between the signal circuit terminal 1 and ground.

⇒	If less than the specified value, test the signal circuit for a short to ground, or an open/high resistance. If the circuit tests normal, replace the BCM.

8. Test for 0 volt between the circuit terminal 4 and ground.

⇒	If greater than the specified value, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM.

9. Test for ignition voltage between the ignition circuit terminal 1 and the signal circuit terminal 4.

⇒	If less than the specified value, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the BCM.

10. If all circuits test normal, test or replace the switch.

Caution: Refer to SIR Caution in the Preface section.

1. Ignition OFF, disconnect the harness connector at the left steering wheel control switch.
2. Test the for less than 2,500 ohms between the ignition circuit terminal 1 and the signal circuit terminal 5.

⇒	If not the specified range, replace the steering wheel control switch.

3. Test for infinite resistance between the ignition circuit terminal 1 and the signal terminal 4 with the switch in the open position.

⇒	If not the specified range, replace the steering wheel control switch.

4. Test the for less than 2,500 ohms between the ignition circuit terminal 1 and the signal terminal 4 with the switch in the closed position.

⇒	If greater than the specified range, replace the left steering wheel control switch.

5. Disconnect the harness connector at the right steering wheel control switch.
6. Test for infinite resistance between the signal circuit terminal 1 and the signal circuit terminal 4 with the switch in the open position.

⇒	If not the specified range, replace the steering wheel control switch.

7. Test for less than 3,000 ohms between the signal terminal 1 and the signal circuit terminal 4 with the switch in the closed position.

⇒	If greater than the specified range, replace the steering wheel control switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.