Instrument cluster

DESCRIPTION

A single instrument cluster is offered on this model. This cluster is an electromechanical unit that utilizes 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. This cluster also incorporates a digital Vacuum Fluorescent Display (VFD) for the odometer/ trip odometer display functions. Some variations of this cluster exist due to optional equipment and regulatory requirements.

This instrument cluster includes the following analog gauges:

• Coolant temperature gauge
• Fuel gauge
• Oil pressure gauge
• Speedometer
• Tachometer
• Voltmeter.

This instrument cluster also includes 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 (programmable)
• Door ajar lamp
• Four-wheel drive lock indicator lamp
• Headlamp high beam indicator lamp
• Liftgate ajar lamp
• Low fuel warning lamp
• Low washer fluid warning lamp
• Malfunction Indicator Lamp (MIL)
• Overdrive-off indicator lamp (automatic transmission - programmable)
• Seat belt reminder lamp
• Security lamp
• Transmission oil temperature warning lamp (automatic transmission - programmable)
• Turn signal indicator lamps
• Upshift indicator lamp (manual transmission - programmable).

The instrument cluster includes a provision for mounting an automatic transmission gear selector indicator in the lower right corner of the cluster. A mechanical gear selector indicator is used with all automatic transmissions except the optional 45RFE to indicate the gear selector position. If the vehicle is equipped with the optional 45RFE automatic transmission, the instrument cluster contains an integral electronic gear selector indicator using a second digital Vacuum Fluorescent Display (VFD) to indicate the gear selector position. The electronic gear selector indicator is controlled by messages received by the instrument cluster from the electronic Transmission Control Module (TCM) over the CCD data bus network.

Models equipped with a manual transmission have a block-out plate installed in place of the gear selector 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, refer to Instrument Cluster in the Diagnosis and Testing section of this group.

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 Warning System in the Description and Operation section of Group 8U - Chime/Buzzer Warning Systems for more information on this feature.

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. The cluster lens, the cluster hood, the rear cluster housing cover, and the incandescent lamp bulbs and holders are available for service replacement.

OPERATION

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.

INDICATOR LAMP

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

The four-wheel drive lock indicator lamp, headlamp high beam indicator lamp, low washer fluid warning lamp, security lamp and turn signal indicator lamps are hard wired. The seat belt reminder lamp is controlled by the instrument cluster programming and by CCD data bus messages from the Airbag Control Module (ACM). The brake warning lamp is controlled by a hard wired input from the park brake switch and by CCD data bus messages from the Controller Anti-lock Brake (CAB). The instrument cluster circuitry uses CCD data bus messages from the Powertrain Control Module (PCM), ACM, and CAB to control all of the remaining indicator lamps.

In addition, certain indicator lamps in this instrument cluster are programmable. This feature allows those indicator lamps to be activated or deactivated with a DRBIIIt scan tool through the instrument cluster electronic circuitry for compatibility with certain optional equipment. The programmable indicator lamps for this model include the cruise-on indicator lamp, the overdrive-off indicator lamp, the transmission oil temperature warning lamp and the upshift indicator lamp.

Except for the cruise-on indicator lamp, the headlamp high beam indicator lamp and the turn signal indicator lamps, each of the indicator lamps in the instrument cluster is illuminated by a dedicated Light-Emitting Diode (LED). If an LED should fail, the entire instrument cluster must be replaced. The cruise-on indicator lamp is part of the odometer VFD display. The headlamp high beam indicator lamp and the turn signal indicator lamps use incandescent bulbs and holders. Each incandescent indicator lamp has a replaceable bulb and bulb holder.

CLUSTER ILLUMINATION LAMP

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 panel lamps dimmer thumbwheel (down to dim, up to brighten). The instrument cluster illumination lamps receive battery feed from the panel dimmer circuitry in the headlamp switch through a fuse in the junction block.

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 instrument cluster Vacuum Fluorescent Display(s) (VFD), and sending dimming level messages over the Chrysler Collision Detection (CCD) data bus network. All VFDs are illuminated at full brightness for improved daylight visibility whenever the park lamps or headlamps are turned off.

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.