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 that is 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

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

Caution: Refer to SIR Caution in the Preface section.

1. Ignition OFF, disconnect the harness connector at the right steering wheel control switch.
2. Ignition ON, Radio ON, test for 8.5-10.5 volts between the supply voltage circuit and ground.

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

⇒	If greater than the specified range, test the supply voltage circuit for short to voltage. If circuit test normal, replace the radio.

3. Test for 8.5-10.5 volts between the supply voltage circuit and the signal circuit.

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

⇒	If greater than the specified range, test the signal circuit for a short to voltage. If the circuit test is 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 and ground.

⇒	If not the specified value, test the signal circuit for a short to ground.

6. 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 right steering wheel control switch.
2. Test for infinite resistance between the signal circuit terminal and voltage circuit terminal with the switch in the open position.

⇒	If not the specified value, replace the switch.

3. Test for less than 6,800 ohms of resistance between the signal circuit and the voltage circuit 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.