Part 7 of 8
SHIFT INDICATOR (TRANSFER CASE)Part Time Indicator
A part time indicator is standard equipment on all instrument clusters, but is only functional on vehicles equipped with the optional four-wheel drive system. The part time indicator is located near the upper edge of the instrument cluster overlay, in the upper right quadrant of the cluster. The part time indicator consists of a stenciled cutout of the words "PART TIME" in the opaque layer of the instrument cluster overlay. The dark outer layer of the overlay prevents the indicator from being clearly visible when the lamp is not illuminated. An amber lens behind the cutout in the opaque layer of the overlay causes the "PART TIME" text to appear in amber through the translucent outer layer of the overlay when it is illuminated from behind by a replaceable incandescent bulb and bulb holder unit located on the instrument cluster electronic circuit board. The part time indicator is serviced as a unit with the instrument cluster.
The part time indicator gives an indication to the vehicle operator that a part time operating mode of the four-wheel drive transfer case is selected. On vehicles with the optional Command-Trac four-wheel drive system, the part time indicator lights when the transfer case is engaged in the 4H or 4L positions. On vehicles with the optional Selec-Trac four-wheel drive system, the part time indicator lights when the transfer case is engaged in the 4 X 4 Part Time or 4 Lo positions. This lamp is hard wired on the instrument cluster electronic circuit board, and is controlled by a transfer case switch input to the cluster. The part time indicator bulb 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 lamp will always be OFF when the ignition switch is in any position except ON or Start.
The transfer case switch is connected in series between ground and the 4WD switch sense (part-time) input to the instrument cluster. Refer to Transfer Case for more information on the transfer case switch. The part time indicator can be diagnosed using conventional diagnostic tools and methods.
Full Time Indicator
A full time indicator is standard equipment on all instrument clusters, but is only functional on vehicles equipped with the optional Selec-Trac four-wheel drive system. The full time indicator is located near the upper edge of the instrument cluster overlay, in the upper right quadrant of the cluster. The full time indicator consists of a stenciled cutout of the words "FULL TIME" in the opaque layer of the instrument cluster overlay. The dark outer layer of the overlay prevents the indicator from being clearly visible when the lamp is not illuminated. However, a green lens behind the cutout in the opaque layer of the cluster overlay causes the "FULL TIME" text to appear in green through the translucent outer layer of the overlay when it is illuminated from behind by a replaceable incandescent bulb and bulb holder unit located on the instrument cluster electronic circuit board. The full time indicator is serviced as a unit with the instrument cluster.
The full time indicator gives an indication to the vehicle operator that a full time operating mode of the four-wheel drive transfer case is selected. The full time indicator lights when the Selec-Trac four-wheel drive transfer case is engaged in the 4 X 4 Full Time position. This lamp is hard wired on the instrument cluster electronic circuit board, and is controlled by a transfer case switch input to the cluster. The full time indicator bulb receives battery current on the instrument cluster electronic circuit board through the fused ignition switch output (START/RUN) circuit whenever the ignition switch is in the ON or Start positions; therefore, the lamp will always be OFF when the ignition switch is in any position except ON or Start.
The transfer case switch is connected in series between ground and the 4WD switch sense (full-time) input to the instrument cluster. Refer to Transfer Case for more information on the transfer case switch. The full time indicator can be diagnosed using conventional diagnostic tools and methods.
SPEEDOMETER
A speedometer is standard equipment in all instrument clusters. The speedometer is located just to the right of center in the instrument cluster. The speedometer consists of a movable gauge needle or pointer controlled by the instrument cluster circuitry and a fixed 210 degree primary outer scale on the cluster overlay that reads up to 100 mph (Domestic), 125 mph (Domestic Police), or 210 km/h (Canada). Each version also has a secondary inner scale on the cluster overlay that provides the equivalent opposite units from the primary scale. A label on the cluster overlay beneath the hub of the speedometer pointer abbreviates the unit of measure for the primary scale in all upper case letters (i.e.: mph or km/h), followed by the unit of measure for the secondary scale in all lower case letters (i.e.: mph or km/h). The gauge needle and gauge scales are clearly visible on the face of the instrument cluster in daylight, and are illuminated from behind by the panel lamps dimmer controlled cluster illumination lighting when the exterior lamps are turned ON. Cluster illumination is provided by replaceable incandescent bulb and bulb holder units located on the instrument cluster electronic circuit board. The speedometer is serviced as a unit with the instrument cluster.
The speedometer gives an indication to the vehicle operator of the road speed of the vehicle. 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 speedometer is an air core magnetic gauge 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:
- Message Failure - If the cluster fails to receive a speedometer message, it will hold the gauge needle at the last indication for about four seconds, or until the ignition switch is turned to the OFF position, whichever occurs first. If a new speedometer message is not received after about four seconds, the gauge needle will return to the far left (low) end of the scale.
- 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 to confirm the functionality of the gauge and the cluster circuitry.
The PCM continually monitors the vehicle speed sensor, then sends the proper messages to the instrument cluster. For further diagnosis of the speedometer or the instrument cluster circuitry that controls the gauge, (Refer to INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING). For proper diagnosis of the PCM, the CCD data bus,or the message inputs to the instrument cluster that control the speedometer, a DRB III scan tool and the appropriate diagnostic information are required.
TACHOMETER
A tachometer is only used in the high-line instrument clusters. The tachometer is located just to the left of center in the instrument cluster. The tachometer consists of a movable gauge needle or pointer controlled by the instrument cluster circuitry and a fixed 210 degree scale on the cluster overlay that reads left-to-right from 0 to 6000 rpm. The gauge needle and gauge scale are clearly visible on the face of the instrument cluster in daylight, and are illuminated from behind by the panel lamps dimmer controlled cluster illumination lighting when the exterior lamps are turned ON. Cluster illumination is provided by replaceable incandescent bulb and bulb holder units located on the instrument cluster electronic circuit board. The tachometer is serviced as a unit with the instrument cluster.
The tachometer gives an indication to the vehicle operator of the engine speed. 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 tachometer is an air core magnetic gauge 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:
- Message Failure - If the cluster fails to receive an engine speed message, it will hold the gauge needle at the last indication for about four seconds, or until the ignition switch is turned to the OFF position, whichever occurs first. If a new engine speed message is not received after about four seconds, the gauge needle will return to the far left (low) end of the scale.
- 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 to confirm the functionality of the gauge and the cluster circuitry.
The PCM continually monitors the crankshaft position sensor, then sends the proper messages to the instrument cluster. For further diagnosis of the tachometer or the instrument cluster circuitry that controls the gauge, (Refer to INSTRUMENT CLUSTER DIAGNOSIS AND TESTING). For proper diagnosis of the PCM, the CCD data bus, or the message inputs to the instrument cluster that control the tachometer, a DRB III scan tool and the appropriate diagnostic information are required.