GM Service Manual Online
For 1990-2009 cars only

Cruise Control Indicator Malfunction IPC Indicator Malfunction

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.

Circuit/System Description

The instrument panel cluster (IPC) illuminates the cruise control engaged indicator based on serial data messages received from the engine control module (ECM). The indicator is commanded ON when the cruise control system is controlling vehicle speed, and turned OFF with the system disengaged.

Reference Information

Schematic Reference

    •  Cruise Control Schematics
    •  Instrument Cluster Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

    •  Cruise Control Description and Operation
    •  Indicator/Warning Message 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 Verification

Ignition ON, with a scan tool perform the Lamp Test for the instrument panel cluster (IPC) and observe the cruise control indicator.

If the cruise control indicator illuminates during the test, replace the ECM.
If the cruise control indicator does not illuminates during the test or remains illuminated at all times, replace the IPC.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM or IPC replacement, setup, and programming

Cruise Control Indicator Malfunction Switch Indicator Malfunction

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

High Resistance

Open

Short to Voltage

Signal Performance

B+ Voltage Reference

1

B3794 08, B3794 6

1

1

B3794 08, B3794 61

Cruise Control Switch Signal

1

B3794 08, B3794 6

1

B3794 08

B3794 08, B3794 61

Cruise Control Switch Indicator Signal

--

2

2

--

--

1. Cruise Control Malfunction

2. Cruise Control Indicator Malfunction

Circuit/System Description

The cruise control switch contains an LED that illuminates to indicate the cruise control system has been switched ON. Voltage is applied through the ON/OFF switch to the LED when the switch is pressed. The BCM provides the ground path for the LED through a dedicated control circuit. Pressing the switch again opens the switch and the lamp turns OFF.

Reference Information

Schematic Reference

Cruise Control Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

    •  Cruise Control Description and Operation
    •  Indicator/Warning Message 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 Verification

Ignition ON, observe the cruise control indicator while applying the cruise On/Off switch. The indicator should turn on and off accordingly with the applied switch.

Circuit/System Testing

Important: Refer to DTC B3794 before performing this diagnostic, if this code is set as current or history.

  1. Ignition OFF, disconnect the harness connector at the steering wheel controls switch - left.
  2. Ignition ON, verify that a test lamp illuminates between the signal circuit terminal 9 and B+.
  3. If the test lamp does not illuminate, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. If all circuits test normal, test or replace the steering wheel controls switch - left.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Steering Wheel Control Switch Assembly Replacement
    •  Control Module References for BCM replacement, setup, and programming