For 1990-2009 cars

### Diagnostic Instructions

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

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
10-Volt Reference | 1 | 1 | 1 | --
Right Steering Wheel Control Switch Signal | 1 | 1 | 1 | --
1. Steering Wheel Controls Inoperative

### Circuit/System Description

The radio supplies voltage to the audio steering wheel control switches and monitors the return signal. Each switch state is associated to a set resistance value and when pressed a specific voltage drop occurs across the resistor unique to the switch. The radio identifies the switch selection and activates the feature.

### Diagnostic Aids

Before diagnosis of the steering wheel controls, ensure the primary controls of the associated component are functioning properly.

### Reference Information

#### Schematic Reference

Steering Wheel Secondary/Configurable Control Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Steering Wheel Controls Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the right steering wheel control switch.
2. Ignition ON, radio ON, test for 9.8-10.2 volts between the voltage reference circuit terminal 2 and ground.

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

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

3. Test for greater than 9 volts between the voltage reference circuit terminal 2 and the signal circuit terminal 1.

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

4. Ignition OFF, disconnect the X2 harness connector at the radio.
5. Test for infinite resistance between the signal circuit terminal 1 and ground.

⇒ | If less than the specified value, test the signal circuit for a short to ground.

6. If all circuits test normal, test or replace the right steering wheel control switch.

### Component Testing

1. Disconnect the harness connector at the right steering wheel control switch.
2. Connect a DMM between terminals 2 and 1 of the right steering wheel control switch.

⇒ | If any of the resistance measurements for the individual switches are not within the specified resistance values, replace the right steering wheel control switch.

Function Switch | Minimum Resistance Value | Maximum Resistance Value
--- | --- | ---
Volume Up | 1.1k Ohms | 1.5k Ohms
Volume Down | 1.4k Ohms | 1.8k Ohms
Next | 1.7k Ohms | 2.1k Ohms
Previous | 2.2k Ohms | 2.6k Ohms
Mute/Voice Activation | 2.9k Ohms | 3.3k Ohms
No Switch Pressed | O.L. | O.L.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Steering Wheel Control Switch Assembly Replacement

• | Control Module References for radio replacement, setup, and programming