Operation

INSTRUMENT CLUSTER
At key ON, the cluster will light the Low Fuel, Seat Belt, Check Gauges, Airbag and/or Smart Key Immobilizer and Upshift lamps (if equipped). As the key is turned farther towards the start position, the ABS (if equipped) and Brake Warning lamp will illuminate. The Vacuum Fluorescent Display (VFD) will indicate the last selected mode, odometer or trip. If there is a bus failure and the cluster cannot receive distance pulses from the PCM, the cluster will display the last mileage stored until the ignition is turned OFF. If the cluster is receiving bus messages but is unable to display odometer information because of an internal failure, the odometer will display dashes. VF dimming is handled by the potentiometer that controls instrumentation illumination. The odometer will remain in the last mode selected, trip or vehicle mileage after each key cycle.

GAUGE
With the ignition switch in the ON or START positions, voltage is supplied to all gauges through the instrument cluster electronic circuit board. With the ignition switch in the Off position, voltage is not supplied to the gauges. The gauges do not accurately indicate any vehicle condition unless the ignition switch is in the On or Start positions.

All of the instrument cluster gauges, except the odometer, are air core magnetic units. Two fixed electromagnetic coils are located within the gauge. These coils are wrapped at right angles to each other around a movable permanent magnet. The movable magnet is suspended within the coils on one end of a shaft. The gauge needle is attached to the other end of the shaft.

One of the coils has a fixed current flowing through it to maintain a constant magnetic field strength. Current flow through the second coil changes, which causes changes in its magnetic field strength. The current flowing through the second coil is changed by the instrument cluster electronic circuitry in response to messages received on the Chrysler Collision Detection (CCD) data bus network.

The gauge needle moves as the movable permanent magnet aligns itself to the changing magnetic fields created around it by the electromagnets. The instrument cluster circuitry is programmed to move all of the gauge needles back to the low end of their respective scales after the ignition switch is turned to the Off position.

REAR WINDOW DEFOGGER
The timing circuit for the rear window defogger is contained in the cluster. The operation is as follows:
With ignition ON, the first push of the defogger button will start a 10 minute timer. After 10 minutes have elapsed, the defogger will be turned OFF. If the button is pushed a second time during the same ignition cycle, the timer will turn the defogger on for 5 minutes. Every consecutive push will operate the defogger for 5 minutes. When the defogger is ON, it can be turned OFF with a second push of the defogger button.

CHIME
The chime function is a 1000 Hz tone contained with in the cluster. The cluster will not generate more than one chime per condition in the same ignition cycle. If a problem occurs that requires a second chime while the first one is currently being generated, the second chime request will be ignored. The chime will sound for the following conditions:

Seat Belt Warning - 6 seconds after key on
Key In Ignition Warning - door open with key in ignition
Engine Temp High - when gauge enters red zone

INDICATOR LAMPS
Indicator lamps are located in the instrument cluster and are served by the cluster circuit board and connectors. Some of the the indicator lamps in the instrument cluster are hardwired while others are controlled by the instrument cluster circuitry in response to messages received over the Chrysler Collision Detection (CCD) data bus network.

The following lamps are hardwired in the cluster and are not part of the self-test.
- Full Time 4WD (export only)
- Part Time 4WD Full Time 4WD (export only)
- Part Time 4WD
- Brake WARNING (red)
- ABS (amber)
- High Beam
- Left Turn Signal
- Right Turn Signal
- Master Illumination (export only)

The following lamps are controlled by the cluster via CCD messages. They are actuated during the self-test procedure.
- Low Fuel Warning Airbag
- Seat Belt
- Upshift (if equipped)
- Check Engine
- Check Gauges
- Smart Key Immobilizer (if equipped)

Each of the indicator lamps in the instrument cluster uses incandescent bulbs and holders, which are available for service replacement.

CLUSTER ILLUMINATION LAMPS
The cluster illumination lamps are hard wired in the instrument cluster. When the park or head lamps are turned on, the cluster illumination lamps light. Illumination brightness is adjusted by rotating the headlamp switch knob (clockwise to dim, counterclockwise to brighten). The instrument cluster illumination lamps receive battery feed from the panel dimmer rheostat in the headlamp switch through a fuse in the fuseblock module.

Hard-wired chime warning system inputs to the instrument cluster include the following:
- Driver door jamb switch
- Driver seat belt switch
- Headlamp switch
- Key-in ignition switch.

The only instrument cluster diagnosis found consists of confirming the viability of the hard-wired chime request inputs to the instrument cluster circuitry. For diagnosis of the CCD data bus and the data bus message inputs, a DRB scan tool and the proper Diagnostic Procedures are recommended.

Refer to Instrument Panel Systems for the instrument cluster service procedures. The instrument cluster chime warning circuitry and chime tone generator cannot be repaired and, if faulty or damaged, the instrument cluster assembly must be replaced.

The instrument cluster electronic circuitry also monitors the cluster illumination lamp dimming level whenever the park or head lamps are turned on. The instrument cluster electronic circuitry responds by adjusting the dimming level of the odometer Vacuum Fluorescent Display (VFD), and sending dimming level messages over the Chrysler Collision Detection (CCD) data bus network. When the park lamps or headlamps are turned off, the VFD is illuminated at full brightness for improved daylight visibility.

Each of the cluster illumination lamps is located on the instrument cluster circuit board. Each cluster illumination lamp has a replaceable bulb and bulb holder.