Diagnostic Instructions
Circuit/System Description
The radio supplies voltage 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.
Diagnostic Aids
| • | This diagnostic is for the audio steering wheel controls. |
| • | Before diagnosis of the steering wheel controls, ensure the primary controls of the associated component are functioning properly. |
| • | Review with the schematic when testing switch resistance values. |
| • | If a single switch function is inoperative, test the suspect switch. Refer to component testing. |
Reference Information
Schematic Reference
Steering Wheel Secondary/Configurable Control Schematics
Connector End View Reference
Description and Operation
Steering Wheel Secondary/Configurable Control Schematics
Electrical Information Reference
Circuit/System Testing
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.
- Ignition OFF, disconnect the harness connector at the right steering wheel control switch.
- Ignition ON, Radio ON, test for 9.5-10.5 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. |
- Test for 9.5-10.5 volts between the 10-volt reference circuit terminal 2 and the signal circuit terminal 4.
| ⇒ | If less than the specified range, test 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. |
- Disconnect the C1 harness connector at the radio.
- Test for infinite resistance between the signal circuit terminal 11 and ground.
| ⇒ | If not the specified value, test the signal circuit for short to ground. |
- If all circuits test normal, test or replace the steering wheel control switch.
Component Testing
Caution: Refer to SIR Caution in the Preface section.
- Ignition OFF, disconnect the harness connector at the right steering wheel control switch.
- 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. |
- Test for less than 3200 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. |
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
