GM Service Manual Online
For 1990-2009 cars only

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

--

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

Ensure the primary controls of the associated component are functioning properly before diagnosis of the steering wheel controls.

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 left and right steering wheel control switches.
  2. Ignition ON, radio ON, test for 9.8-10.2 volts between the voltage reference circuit terminal 5 and ground.
  3. 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.
  4. Test for greater than 9 volts between the voltage reference circuit terminal 5 and the signal circuit terminal 1.
  5. 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.
  6. Ignition OFF, disconnect the X1 harness connector at the radio.
  7. Test for infinite resistance between the signal circuit terminal 1 and ground.
  8. If less than the specified value, test the signal circuit for a short to ground.
  9. Ignition ON, test for less than 1 volt between ground and the voltage reference circuit terminal 4 at the left steering wheel control switch.
  10. If greater than the specified range, test the voltage reference circuit for a short to voltage
  11. Ignition ON, test for infinite resistance between ground and the voltage reference circuit terminal 4 at the left steering wheel control switch.
  12. If not the specified value, test the voltage reference circuit for a short to ground.
  13. Test for less than 1 ohm between the voltage reference circuit terminal 4 at the left steering wheel control switch and the voltage reference circuit terminal 2 at the right steering wheel control switch.
  14. If greater than the specified range, test the voltage reference circuit for a an open/high resistance.
  15. If all circuits test normal, test or replace the left or right steering wheel control switch.

Component Testing

  1. Disconnect the harness connector at the right or left steering wheel control switch.
  2. Connect a DMM between terminals 1 and terminal 4 (left switch) or terminal 5 (right switch) of either the left or right steering wheel control switch.
  3. If any of the resistance measurements for the individual switches are not within the specified resistance values, replace the right steering wheel control switch.

Left Steering Wheel Switch Resistance

Function Switch

Minimum Resistance Value

Maximum Resistance Value

Previous

500 Ohms

900 Ohms

Seek

1.7k Ohms

2.1k Ohms

Next

4.1k Ohms

4.5k Ohms

Source

11.0k Ohms

11.4k Ohms

No Switch Pressed

O.L.

O.L.


Right Steering Wheel Switch Resistance

Function Switch

Minimum Resistance Value

Maximum Resistance Value

Volume Up

1.1k Ohms

1.3k Ohms

Volume Down

1.4k Ohms

1.8k Ohms

Play

1.7k Ohms

2.1k Ohms

Mute

2.2k Ohms

2.6k 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