RAM 1500 Van V8-5.9L VIN Z (1998)
Cruise Control Indicator Lamp: Description and Operation
SYSTEM OPERATION
The cruise-on indicator lamp gives an indication when the vehicle speed control system is turned on even when the system is not currently
engaged. The lamp is turned on by the instrument cluster circuitry for about two seconds when the ignition switch is turned to the On position as a
bulb test. After the bulb test, the lamp is controlled by the instrument cluster circuitry based upon messages received from the Powertrain Control
Module (PCM) on the Chrysler Collision Detection (CCD) data bus.
The PCM uses an input from the analog resistor-multiplexed vehicle speed control switches in the steering wheel to decide whether to turn the
lamp on or off. The PCM then sends the proper messages to the instrument cluster on the CCD data bus.
