Cruise Control Malfunction Without K59

The cruise control switch is an input to the body control module (BCM). The BCM monitors the cruise control on/off, set/coast, resume/accelerate and cancel switches via the cruise control 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 switch signal circuit when a switch is applied. The BCM sends a serial data message to the ECM indicating the status of the cruise control switches.

Schematic Reference

Cruise Control Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Cruise Control Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Engine ON, while rotating the steering wheel to both steering stops, observe the scan tool Cruise Control Switch and the Cruise Cancel Switch parameter while pressing each of the cruise control switches. The parameter should toggle between On, Off, Resume, Set and Cancel as the applicable switch is pressed.

1. Ignition OFF, disconnect the X1 harness connector at the turn signal/multifunction switch.
2. Ignition ON, test for B+ between the B+ circuit terminal 1 and ground.

⇒	If less than the specified value, test the circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

3. Test for B+ between the B+ circuit terminal 1 and the signal circuit terminal 5.

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

4. Ignition OFF, disconnect the X2 harness connector at the BCM.
5. Test for infinite resistance between the signal circuit terminal 61 and ground.

⇒	If less than the specified value, test the signal circuit for a short to ground.

6. If all circuits test normal, test or replace the turn signal/multifunction switch.

1. Disconnect the X1 harness connector at the turn signal/multifunction switch.
2. Cruise control switch ON, measure the resistance between terminal 1 and terminal 5 while individually activating and holding each cruise control function switch and compare the resistance reading to the values in the table below.

⇒	If not within the specified resistance range, replace the turn signal/multifunction switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.