Liberty Sport 2WD L4-2.4L VIN 1 (2002)
Cruise Control Indicator Lamp: Description and Operation
A cruise indicator is standard equipment on all instrument clusters, but is only functional on vehicles equipped with the optional speed control system.
The cruise indicator is located near the lower edge of the instrument cluster, between the tachometer and the speedometer. The cruise indicator consists
of a stencil-like cutout of the word "CRUISE" in the opaque layer of the instrument cluster overlay. The dark outer layer of the overlay prevents the
indicator from being clearly visible when it is not illuminated. A green Light Emitting Diode (LED) behind the cutout in the opaque layer of the overlay
causes the "CRUISE" text to appear in green through the translucent outer layer of the overlay when it is illuminated from behind by the LED, which is
soldered onto the instrument cluster electronic circuit board. When the exterior lighting is turned ON, the illumination intensity of the cruise indicator is
dimmable, which is adjusted using the panel lamps dimmer control ring on the left control stalk of the multi-function switch. The cruise indicator is
serviced as a unit with the instrument cluster.
The cruise indicator gives an indication to the vehicle operator when the speed control system is turned ON, regardless of whether the speed control is
engaged. This indicator is controlled by a transistor on the instrument cluster electronic circuit board based upon the cluster programming and electronic
messages received by the cluster from the Powertrain Control Module (PCM) over the Programmable Communications Interface (PCI) data bus. The
cruise indicator Light Emitting Diode (LED) is completely controlled by the instrument cluster logic circuit, and that logic will only allow this indicator
to operate when the instrument cluster receives a battery current input on the fused ignition switch output (run- start) circuit. Therefore, the LED will
always be OFF when the ignition switch is in any position except ON or Start. The LED only illuminates when it is provided a path to ground by the
instrument cluster transistor. The instrument cluster will turn ON the cruise indicator for the following reasons:
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Cruise Lamp-ON Message - Each time the cluster receives a cruise lamp-on message from the PCM indicating the speed control system has been
turned ON, the cruise indicator is illuminated. The indicator remains illuminated until the cluster receives a cruise lamp-OFF message from the
PCM or until the ignition switch is turned to the OFF position, whichever occurs first.
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Actuator Test - Each time the cluster is put through the actuator test, the cruise indicator will be turned ON, then OFF again during the bulb check
portion of the test in order to confirm the functionality of the LED and the cluster control circuitry
The PCM continually monitors the speed control switches to determine the proper outputs to the speed control servo. The PCM then sends the proper
cruise indicator lamp-on and lamp-OFF messages to the instrument cluster. For further diagnosis of the cruise indicator or the instrument cluster circuitry
that controls the indicator, (Refer to INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING). For proper diagnosis of the speed control system, the
PCM, the PCI data bus, or the electronic message inputs to the instrument cluster that control the cruise indicator, a DRBIII scan tool is required. Refer
to the appropriate diagnostic information.
