Part 3A

CRUISE INDICATOR
A cruise indicator is standard equipment on all instrument clusters. However, on vehicles not equipped with the optional speed control system, this indicator is electronically disabled. The cruise indicator consists of the word "CRUISE", which appears in the lower portion of the odometer/trip odometer Vacuum-Fluorescent Display (VFD). The VFD is part of the cluster electronic circuit board, and is visible through a cutout located in the lower left corner of the cluster overlay. The dark lens of the VFD prevents the indicator from being clearly visible when it is not illuminated. The word "CRUISE" appears in an amber color and at the same lighting level as the odometer/trip odometer information when it is illuminated by the instrument cluster electronic circuit board. The cruise indicator lamp is serviced as a unit with the VFD in 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 the instrument cluster circuit board based upon the cluster programming and electronic messages received by the cluster from the Powertrain Control Module (PCM) over the Chrysler Collision Detection (CCD) data bus. The cruise indicator receives battery current on the instrument cluster electronic circuit board through the fused ignition switch output (ST/RUN) circuit whenever the ignition switch is in the ON or Start positions; therefore, the indicator will always be OFF when the ignition switch is in any position except ON or Start. The indicator only illuminates when it is switched to ground by the instrument cluster circuitry. The instrument cluster will turn ON the cruise indicator for the following reasons:
- Bulb Test - Each time the ignition switch is turned to the ON position the cruise indicator is illuminated for about two seconds as a bulb test.
- 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.
- Actuator Test - Each time the cluster is put through the actuator test, the cruise indicator will be turned ON during the VFD portion of the test to confirm the functionality of the VFD, and again during the bulb check portion of the test to confirm the functionality of 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 ELECTRICAL/INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING). For proper diagnosis of the speed control system, the PCM, the CCD data bus, or the message inputs to the instrument cluster that control the cruise indicator, a DRB III scan tool is required. Refer to the appropriate diagnostic information.

ENGINE TEMPERATURE GAUGE
An engine coolant temperature gauge is standard equipment on all instrument clusters. The engine coolant temperature gauge is located in the lower left quadrant of the instrument cluster, below the voltage gauge. The engine coolant temperature gauge consists of a movable gauge needle or pointer controlled by the instrument cluster circuitry and a fixed 90 degree scale on the cluster overlay that reads left-to- right from 54 °C (130 °F) to 127 °C (260 °F) for gasoline engines, or from 60 °C (140 °F) to 116 °C (240 °F) for diesel engines. An International Control and Display Symbol icon for "Engine Coolant Temperature" is located on the cluster overlay, directly below the lowest graduation of the gauge scale. The engine coolant temperature gauge graphics are white against a black field except for a single red graduation at the high end of the gauge scale, making them clearly visible within the instrument cluster in daylight. When illuminated from behind by the panel lamps dimmer controlled cluster illumination lighting with the exterior lamps turned ON, the white graphics appear blue-green and the red graphics appear red. The orange gauge needle is internally illuminated. Gauge illumination is provided by replaceable incandescent bulb and bulb holder units located on the instrument cluster electronic circuit board. The engine coolant temperature gauge is serviced as a unit with the instrument cluster.

The engine coolant temperature gauge gives an indication to the vehicle operator of the engine coolant temperature. This gauge is controlled by the instrument cluster circuit board based upon the cluster programming and electronic messages received by the cluster from the Powertrain Control Module (PCM) over the Chrysler Collision Detection (CCD) data bus. The engine coolant temperature gauge is an air core magnetic unit that receives battery current on the instrument cluster electronic circuit board through the fused ignition switch output (ST/RUN) circuit whenever the ignition switch is in the ON or Start positions. The cluster is programmed to move the gauge needle back to the low end of the scale after the ignition switch is turned to the OFF position. The instrument cluster circuitry controls the gauge needle position and provides the following features:
- Engine Temperature Message - Each time the cluster receives a message from the PCM indicating the engine coolant temperature is between the low end of normal [about 57 °C (130 °F) for gasoline engines, or 60 °C (140 °F) for diesel engines] and the high end of normal [about 129 °C (264 °F) for gasoline engines, or 116 °C (240 °F) for diesel engines], the gauge needle is moved to the actual temperature position on the gauge scale.
- Engine Temperature Low Message - Each time the cluster receives a message from the PCM indicating the engine coolant temperature is below the low end of normal [about 57 °C (130 °F) for gasoline engines, or 60 °C (140 °F) for diesel engines], the gauge needle is held at the lowest increment [57 °C (130 °F) for gasoline engines, or 60 °C (140 °F) for diesel engines] at the far left end of the gauge scale. The gauge needle remains at the far left end of the scale until the cluster receives a message from the PCM indicating that the engine temperature is above about 57 °C (130 °F) for gasoline engines, or 60 °C (140 °F) for diesel engines, or until the ignition switch is turned to the OFF position, whichever occurs first.
- Engine Temperature High Message - Each time the cluster receives a message from the PCM indicating the engine coolant temperature is above about 122 °C (253 °F) for gasoline engines, or 112 °C (233 °F) for diesel engines, the gauge needle is moved to the appropriate position on the gauge scale, the check gauges indicator is illuminated, and a single chime tone is sounded. The check gauges indicator remains illuminated until the cluster receives a message from the PCM indicating that the engine temperature is below about 119 °C (246 °F) for gasoline engines, or 109 °C (226 °F) for diesel engines, or until the ignition switch is turned to the OFF position, whichever occurs first. The chime tone feature will only repeat during the same ignition cycle if the check gauges indicator is cycled OFF and then on again by the appropriate engine temperature messages from the PCM.
- Message Failure - If the cluster fails to receive an engine temperature message, it will hold the gauge needle at the last indication until a new message is received, or until the ignition switch is turned to the OFF position, whichever occurs first.
- Actuator Test - Each time the cluster is put through the actuator test, the gauge needle will be swept to several calibration points on the gauge scale in a prescribed sequence in order to confirm the functionality of the gauge and the cluster control circuitry.

The PCM continually monitors the engine coolant temperature sensor to determine the engine operating temperature. The PCM then sends the proper engine coolant temperature messages to the instrument cluster. For further diagnosis of the engine coolant temperature gauge or the instrument cluster circuitry that controls the gauge, (Refer to ELECTRICAL/INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING). If the instrument cluster turns ON the check gauges indicator due to a high engine temperature gauge reading, it may indicate that the engine or the engine cooling system requires service. For proper diagnosis of the engine coolant temperature sensor, the PCM, the CCD data bus, or the message inputs to the instrument cluster that control the engine coolant temperature gauge, a DRB III scan tool is required. Refer to the appropriate diagnostic information.

FUEL GAUGE
A fuel gauge is standard equipment on all instrument clusters. The fuel gauge is located in the lower right quadrant of the instrument cluster, below the oil pressure gauge. The fuel gauge consists of a movable gauge needle or pointer controlled by the instrument cluster circuitry and a fixed 90 degree scale on the cluster overlay that reads left-to-right from E (or Empty) to F (or Full). An International Control and Display Symbol icon for "Fuel" is located on the cluster overlay, directly below the highest graduation of the gauge scale. The text "FUEL DOOR" and an arrowhead pointed to the left side of the vehicle is imprinted on the cluster overlay directly below the fuel gauge to provide the driver with a reminder as to the location of the fuel filler access. The fuel gauge graphics are white against a black field except for a single red graduation at the low end of the gauge scale, making them clearly visible within the instrument cluster in daylight. when illuminated from behind by the panel lamps dimmer controlled cluster illumination lighting with the exterior lamps turned ON, the white graphics appear blue-green and the red graphics appear red. The orange gauge needle is internally illuminated. Gauge illumination is provided by replaceable incandescent bulb and bulb holder units located on the instrument cluster electronic circuit board. The fuel gauge is serviced as a unit with the instrument cluster.

The fuel gauge gives an indication to the vehicle operator of the level of fuel in the fuel tank. This gauge is controlled by the instrument cluster circuit board based upon the cluster programming and electronic messages received by the cluster from the Powertrain Control Module (PCM) over the Chrysler Collision Detection (CCD) data bus. The fuel gauge is an air core magnetic unit that receives battery current on the instrument cluster electronic circuit board through the fused ignition switch output (ST/RUN) circuit whenever the ignition switch is in the ON or Start positions. The cluster is programmed to move the gauge needle back to the low end of the scale after the ignition switch is turned to the OFF position. The instrument cluster circuitry controls the gauge needle position and provides the following features:
- Percent Tank Full Message - Each time the cluster receives a message from the PCM indicating the percent tank full, the cluster programming applies an algorithm to calculate the proper gauge needle position, then moves the gauge needle to the proper position on the gauge scale. The algorithm is used to dampen gauge needle movement against the negative effect that fuel sloshing within the fuel tank can have on accurate inputs from the fuel tank sending unit to the PCM.
- Less Than 12.5 Percent Tank Full Message - Each time the cluster receives messages from the PCM indicating the percent tank full is 12.5 (one- eighth) or less for 10 consecutive seconds and the vehicle speed is zero, or for 60 consecutive seconds and the vehicle speed is greater than zero, the gauge needle is moved to the proper position on the gauge scale, the low fuel indicator is illuminated, and a single chime tone is sounded. The low fuel indicator remains illuminated until the cluster receives messages from the PCM indicating that the percent tank full is greater than 12.5 (one-eighth) for 10 consecutive seconds and the vehicle speed is zero, or for 60 consecutive seconds and the vehicle speed is greater than zero, or until the ignition switch is turned to the OFF position, whichever occurs first. The chime tone feature will only repeat during the same ignition cycle if the low fuel indicator is cycled OFF and then on again by the appropriate percent tank full messages from the PCM.
- Less Than Empty Percent Tank Full Message - Each time the cluster receives a message from the PCM indicating the percent tank full is less than empty, the gauge needle is moved to the far left (low) end of the gauge scale and the low fuel indicator is illuminated immediately This message would indicate that the fuel tank sender input to the PCM is a short circuit.
- More Than Full Percent Tank Full Message - Each time the cluster receives a message from the PCM indicating the percent tank full is more than full, the gauge needle is moved to the far left (low) end of the gauge scale and the low fuel indicator is illuminated immediately. This message would indicate that the fuel tank sender input to the PCM is an open circuit.
- Message Failure - If the cluster fails to receive a percent tank full message, it will hold the gauge needle at the last indication until a new message is received, or until the ignition switch is turned to the OFF position, whichever occurs first.
- Actuator Test - Each time the cluster is put through the actuator test, the gauge needle will be swept to several calibration points on the gauge scale in a prescribed sequence in order to confirm the functionality of the gauge and the cluster control circuitry.

The PCM continually monitors the fuel tank sending unit, then sends the proper messages to the instrument cluster. For further diagnosis of the fuel gauge or the instrument cluster circuitry that controls the gauge, (Refer to ELECTRICAL/INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING).

For proper diagnosis of the fuel tank sending unit, the PCM, the CCD data bus, or the message inputs to the instrument cluster that control the fuel gauge, a DRB III scan tool is required. Refer to the appropriate diagnostic information.