The radio supplies voltage to the audio steering wheel control 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 radio then identifies the selection to activate the feature, otherwise sends a serial data message received by the controlled component activating the feature.

Schematic Reference

Steering Wheel Secondary/Configurable Control Schematics

Connector End View Reference

Description and Operation

Steering Wheel Controls Description and Operation

Electrical Information Reference

Scan Tool Reference

Scan Tool Data List

Ignition ON, Radio ON, observe the scan tool Volume Control parameter. The reading should increase percentage or decrease percentage while pressing the volume up or down button.

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

1. Ignition OFF, disconnect the harness connector at the right steering wheel control switch.
2. Ignition ON, Radio ON, test for 7.5-8.5 volts between the ignition circuit terminal 2 and ground.

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

⇒	If greater than the specified range, test the ignition circuit for a short to B+. If the circuit tests normal, replace the radio.

3. Test for 7.5-8.5 volts between the ignition circuit terminal 2 and the signal circuit terminal 4.

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

⇒	If greater than the specified range, test the signal circuit for a short to B+. If the circuit tests normal, replace the radio.

4. Ignition OFF, disconnect the C1 harness connector at the radio.
5. Test for infinite resistance between the signal circuit terminal A7 and ground.

⇒	If not the specified value, test the signal circuit for a short to ground. If the circuit tests normal, test or replace the switch.

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

1. Ignition OFF, disconnect the harness connector at the right steering wheel control switch.
2. Test for infinite resistance between the signal terminal 4 and the ignition terminal 2 with the switch in the open position.

⇒	If not the specified value, replace the switch.

3. Test for less than 3200 ohms between the signal circuit terminal and the ignition circuit terminal with the switch in the closed position.

⇒	If greater than the specified range, replace the switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.