Radio Control Multi-Function Switch Malfunction

Radio Control Multi-Function Switch Malfunction

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions)provides an overview of each diagnostic category.

Circuit/System Description

The radio control multi-function switch interfaces with the info display module which communicates with the radio/HVAC control through a LIN interface. The info display module is responsible for passing information between the radio and the radio/HVAC control.

Diagnostic Aids

* This diagnostic is for the radio control multi-function switch.
* Before diagnosis of the radio control multi-function switch, ensure the primary controls of the associated cellular, entertainment and navigation (radio) component are functioning properly.

Reference Information
Schematic Reference

Radio/Navigation System Schematics (Radio/Navigation System Schematics)
Connector End View Reference

Component Connector End Views (Connector End Views By Name)
Description and Operation

* Data Link Communications Description and Operation (Description and Operation)
* Radio/Audio System Description and Operation (Radio/Audio System)

Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning)for scan tool information

Circuit/System Verification

1. Ignition ON, cellular, entertainment and navigation (radio) ON.
2. Press and/or scroll each of the buttons on the radio control switch.
3. The cellular, entertainment and navigation (radio) should respond to desired function of the radio switch.
4. Ignition ON, observe the DTC information with a scan tool. Verify no DTCs are set.

• If a DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code (DTC) List - Vehicle).

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the S56 radio control multi-function switch.
2. Test for less than 30 ohm between ground circuit terminal 2 and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, verify that a test lamp illuminates between B+ circuit terminal 1 and ground.

• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

4. Test for 2-11.5 V between the serial data circuit terminal 3 and ground.

• If greater than the specified range, test the serial data circuit for a short to voltage. If the circuit tests normal, replace the P17 info display module.
• If less than the specified range, test the serial data circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the P17 info display module.

5. If all circuits test normal, replace the S56 radio control multi-function switch.

Repair Instructions

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

* GMLAN Wiring Repairs (GMLAN Wiring Repairs)
* Control Module References (Programming and Relearning)for control module replacement, programming and setup