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.

### Circuit/System Description

The cruise control switch is an input to the body control module (BCM). The BCM monitors the cruise control set/coast and resume/accelerate switch signal circuit in order to detect when the driver has requested to perform a cruise control function. The BCM detects a specific voltage signal on the cruise control set/coast and resume/accelerate switch signal circuit when a switch is applied. The BCM sends a GMLAN serial data message to the ECM indicating the status of the cruise control switches.

### Conditions for Enabling Cruise Control

• | The vehicle speed is greater than 40 km/h (25 mph).

• | The vehicle is not in PARK, REVERSE, NEUTRAL, or 1st gear.

• | The system voltage is within 9-16 volts.

• | The park brake or brakes are not applied.

### Reference Information

#### Schematic Reference

Cruise Control Schematics

#### Connector End View Reference

Cruise Control Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

### Circuit/System Verification

Important: Repair any brake system related symptoms and DTCs before performing this diagnostic.

Important: If a BCM has been replaced, the brake pedal position (BPP) sensor must be calibrated. Refer to Brake Pedal Position Sensor Calibration .

Ignition ON, observe the scan tool Cruise Control Switch parameter while pressing the cruise control switches. The reading should change between On, Off, Resume, Set and Cancel accordingly with the depressed switches.

### Circuit/System Testing

1. Ignition OFF, remove the inflatable restraint steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement .
2. Disconnect the harness connector of the steering wheel controls switch - left.
3. Ignition ON, test for 10 volts or greater between the steering wheel control supply voltage circuit terminal 1 and ground.

⇒ | If less than 10 volts, check for an open/high resistance or for a short to ground on the steering wheel control supply voltage circuit. If the circuit tests normal, replace the BCM.

4. Ignition ON, verify that a test lamp illuminates between B+ and the cruise control switch signal circuit terminal 3.

⇒ | If the test lamp does not illuminate, test the cruise control switch signal circuit for an open/high resistance. If the circuit tests normal, replace the BCM.

5. Ignition OFF, disconnect the harness connector C1 at the BCM.
6. Measure for 0 volts between the cruise control switch signal circuit terminal 3 and ground.

⇒ | If greater than the specified value, test the cruise control switch signal circuit for a short to voltage.

7. If all circuits test normal, test the component. If the circuits and the component tests are normal, replace the BCM.

### Component Testing

Important: The cruise control ON/OFF switch must be ON in order to properly measure the resistance of the - SET, the + RES, and the Cancel switches.

#### Steering Wheel Controls Switch - Left

1. Ignition OFF, remove the inflatable restraint steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement .
2. Ignition OFF, disconnect the steering wheel controls switch - left.
3. Cruise switch ON, measure the resistance between terminals 1 and 3 at the cruise control switch side of the connector. Individually activate and hold each cruise control function switch and compare the resistance reading to the values on the schematic for the ON/OFF, SET -, the RES +, and the Cancel switches.

⇒ | If any of the resistance measurements for the OFF, ON, SET -, RES + and Cancel switches are not within the listed resistance values, replace the steering wheel controls switch - left.

Function Switch | Minimum Resistance Value | Maximum Resistance Value
--- | --- | ---
OFF | O.L. | O.L.
ON | 6.5k Ohms | 7.0k Ohms
- SET | 2.2k Ohms | 2.4k Ohms
+ RES | 3.7k Ohms | 3.8k Ohms
Cancel | 1.4k Ohms | 1.6k Ohms

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Steering Wheel Control Switch Assembly Replacement

• | Control Module References for BCM or ECM replacement, setup, and programming