Steering Wheel Controls Inoperative 4-Spoke

The radio supplies 10 volts 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 radio will perform the desired function, or send a serial data message to another component.

Schematic Reference

Steering Wheel Secondary/Configurable Control Schematics

Connector End View Reference

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 9.2-10 volts between the 10-volt reference circuit terminal and ground.

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

3. Test for 9.2-10 volts between the 10-volt reference circuit terminal 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 voltage. If the circuit tests normal, replace the radio.

4. Connect a 3A fused jumper wire between the 10-volt reference circuit terminal 1 and the signal circuit terminal 5.
5. Disconnect the harness connector at the left steering wheel control switch.
6. Test for 9.2-10 volts between the signal circuit terminal 1 and ground.

⇒	If less than the specified range, test the signal 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 signal circuit for a short to voltage. If the circuit tests normal, replace the radio.

7. Test for 9.2-10 volts between the signal circuit terminal 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 voltage. If the circuit tests normal, replace the radio.

8. Disconnect the C1 harness connector at the radio.
9. Test for infinite resistance between the signal circuit terminal A9 and ground.

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

10. 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 less the 2,400 ohms of resistance between the signal circuit terminal 5 and the 10-volt reference terminal 1.

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

3. Test for infinite resistance between the signal circuit terminal 4 and the 10-volt reference terminal 1 with the switch in the open position.

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

4. Test for less than 2,400 ohms of resistance between the signal circuit terminal 4 and the 10-volt reference terminal with the switch in the closed position.

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

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

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

7. Test for less than 12,000 ohms of resistance between the signal circuit terminal 4 and the signal circuit terminal with the switch in the closed position.

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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Steering Wheel Controls Inoperative 3-Spoke

The radio supplies 10 volts 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 radio will perform the desired function, or send a serial data message to another component.

Schematic Reference

Steering Wheel Secondary/Configurable Control Schematics

Connector End View Reference

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 9.2-10 volts between the 10-volt reference circuit terminal 2 and ground.

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

3. Test for 9.2-10 volts between the 10-volt reference 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 voltage. If the circuit tests normal, replace the radio.

4. Disconnect the C1 harness connector at the radio.
5. Test for infinite resistance between the signal circuit terminal A9 and ground.

⇒	If not the specified value, test the signal circuit for 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 signal circuit terminal 4 and the 10-volt reference terminal 2 with the switch in the open position.

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

3. Test for less than 3,200 ohms of resistance between the signal circuit terminal 4 and the 10-volt reference terminal 2 with the switch in the closed position.

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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.