Instrument Panel, Gauges and Warning Indicators: Description and Operation
INSTRUMENT CLUSTER
Two basic instrument cluster options are offered on this model. One is referred to as a low-line cluster, and the other is referred to as a high-line cluster. Both clusters are electromechanical units that utilize integrated circuitry and information carried on the Chrysler Collision Detection (CCD) data bus network for control of all gauges and many of the indicator lamps. These clusters also incorporate a Liquid Crystal Display (LCD) for the digital odometer/trip odometer display functions. Some variations of these clusters exist due to optional equipment and regulatory requirements.
Both of these clusters include the following analog gauges:
- Coolant temperature gauge
- Fuel gauge
- Oil pressure gauge
- Speedometer
- Voltmeter
These clusters also include provisions for the following indicator lamps:
- Airbag indicator lamp
- Anti-Lock Brake System (ABS) lamp
- Brake warning lamp
- Check gauges lamp
- Cruise-on indicator lamp
- Four-wheel drive indicator lamp
- Headlamp high beam indicator lamp
- Low fuel warning lamp
- Low washer fluid warning lamp
- Malfunction indicator (Check Engine) lamp
- Overdrive-off indicator lamp (automatic transmission)
- Seat belt reminder lamp
- Security lamp
- Service Reminder Indicator (SRI) lamp (Maintenance Required-for certain heavy duty emissions cycle engines)
- Transmission oil temperature warning lamp (automatic transmission)
- Turn signal indicator lamps
- Upshift indicator lamp (manual transmission)
- Wait-to-start indicator lamp (diesel engine)
- Water-in-fuel indicator lamp (diesel engine)
The high-line cluster includes all of the gauges and indicator lamps found in the low-line cluster, but adds an analog tachometer. Some of the low-line cluster gauges have different positions or sizes in the high-line cluster in order to accommodate the tachometer.
Both instrument clusters also have a provision for mounting the automatic transmission gear selector indicator in the lower right corner of the cluster. Models equipped with a manual transmission have a block-out plate installed in place of this indicator.
The instrument cluster circuitry has a self-diagnostic actuator test capability, which will test each of the CCD bus message-controlled functions of the cluster by lighting the appropriate indicator lamps and positioning the gauge needles at several predetermined locations on the gauge faces in a prescribed sequence. For more information on this function, see Instrument Clusters in the Diagnosis and Testing section.
The instrument cluster circuitry also sends chime tone requests over a hard-wired circuit to the Central Timer Module (CTM) when it monitors certain conditions or inputs. The CTM replaces the chime or buzzer module. Refer to Chime/Buzzer Warning Systems for more information on this cluster circuitry function.
The instrument cluster for this model is serviced only as a complete unit. If a cluster gauge or the cluster circuit board are faulty, the entire cluster must be replaced. Each of the red indicators in the cluster are illuminated by a Light-Emitting Diode (LED). If an LED fails, the entire instrument cluster must be replaced. The cluster lens, the cluster hood, the rear cluster housing cover, and the incandescent lamp bulbs and holders are available for service replacement.
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.