Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

The radio supplies voltage to the 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 switch selected to activate the feature, otherwise sends a serial data message received by the controlled component activating the feature.

Schematic Reference

Steering Wheel Schematics

Connector End View Reference

Entertainment Connector End Views

Electrical Information Reference

Caution: Refer to SIR Caution in the Preface section.

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 left and right steering wheel control switches.
2. Ignition ON, Radio ON, test for 6.5-9 volts between the voltage circuit and ground at the right switch harness connector.

⇒	If less than 6.5 volts, test the voltage circuit for short to ground or open/high resistance. If circuit tests normal, replace the radio.

⇒	If greater than 9 volts, test the voltage circuit for short to voltage. If circuit tests normal, replace the radio.

3. Test for 6.5-9 volts from the voltage circuit and toggle to the signal circuits at the left and right switch harness connectors.

⇒	If less than 6.5 volts, test the signal circuit for an open/high resistance. If circuit tests normal, replace the radio.

⇒	If greater than 9 volts, test the signal circuit for short to voltage. If circuit tests normal, replace the radio.

4. Ignition OFF, reconnect the right switch.
5. Ignition ON, Radio ON, test for 6.5-9 volts between the voltage circuit and the left switch and ground at the left switch harness connector.

⇒	If less than 6.5 volts, test the voltage circuit to the left switch for a short to ground or open/high resistance. If the circuit tests normal, refer to component testing.

⇒	If greater than 9 volts, test the voltage supply circuit for the left switch for a short to B+.

6. Pressing the right switch, test for 1-5 volts between the signal circuit and ground at the left switch harness connector.

⇒	If less than 1 volt, test the signal circuit for a short to ground.

7. If all circuits test normal, refer to component testing.

Caution: Refer to SIR Caution in the Preface section.

1. Ignition OFF, disconnect the harness connector at the steering wheel control switches.
2. Test the right switch for 2360-2400 ohms of resistance between the voltage terminal and the terminal supplying voltage for the left switch.

⇒	If the resistance is not between 2360-2400 ohms, replace the faulty switch.

3. 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.

4. 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.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.