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

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 right steering wheel control switch.
2. Ignition ON, Radio ON, test for 8.5-10.5 volts between the 10-volt reference circuit terminal 2 and ground.

⇒	If less than the specified range, test 10-volt reference circuit for short to ground or open/high resistance. If the circuit tests normal, replace the radio.

⇒	If greater than the specified range, test the 10-volt reference circuit for a short to voltage. If the circuit tests normal, replace the radio.

3. Test for 8.5-10.5 volts between the 10-volt reference circuit terminal 2 and the signal circuit terminal 4.

⇒	If less than the specified range, test 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 voltage. 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 11 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 steering wheel control 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 10-volt reference terminal 2 and the signal terminal 2 with the switch in the open position.

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

3. Test for less than 3,100 ohms between the 10-volt reference terminal 2 and the signal terminal 4 with the switch closed in each position and verify readings are approximate to what the schematic reads.

⇒	If less than the specified value, replace the steering wheel switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.