Steering Wheel Controls Inoperative

Steering Wheel Controls Inoperative

Diagnostic Fault Information

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview

Circuit/System Description

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.

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 schematic when testing switch resistance values.
* If a single switch function is inoperative, test the suspect switch. Refer to component testing.

Circuit/System Testing

Caution: Refer to Restraint System Service Precautions.

Important: It is recommended that Component Testing be 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 ignition voltage circuit terminal 2 and ground.

• If less than the specified value, test the ignition voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
• If greater than the specified value, test the ignition voltage circuit for a short to voltage. If the circuit tests normal, replace the radio.

3. Test for 8.5-10.5 volts between the ignition voltage circuit and the signal circuit terminal 4.

• If less than the specified value, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the radio.
• If greater than the specified value, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.

4. Ignition OFF, disconnect the 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. If the circuit tests normal, test or replace the switch.

6. If all circuits test normal, test or replace the switch.

Component Testing

Caution: Refer to Restraint System Service Precautions.

1. Ignition OFF, disconnect the harness connector at the right steering wheel control switch.
2. Test for infinite resistance between the signal terminal 4 and the ignition terminal 2 with the switch in the open position.

• If not the specified value, replace the switch.

3. Test the resistance values between the signal terminal and the ignition terminal with the switch closed in each position. Verify values are approximate to what the schematic reads.

• If values do not match, replace the switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

* Steering Wheel Control Switch Assembly Replacement
* Refer to Programming and Relearning.Programming and Relearning