Part 4A
SEATBELT INDICATORA seatbelt indicator is standard equipment on all instrument clusters. The seatbelt indicator is located near the center of the instrument cluster overlay, directly below the high beam indicator and above the odometer/trip odometer Vacuum Fluorescent Display (VFD). The seatbelt indicator consists of a stencil-like cutout of the International Control and Display Symbol icon for "Seat Belt" in the opaque layer of the instrument cluster overlay. The dark outer layer of the overlay prevents the indicator from being clearly visible when it is not illuminated. A red lens behind the cutout in the opaque layer of the overlay causes the icon to appear in red through the translucent outer layer of the overlay when the indicator is illuminated from behind by a Light Emitting Diode (LED) soldered onto the instrument cluster electronic circuit board. The seatbelt indicator is serviced as a unit with the instrument cluster.
The seatbelt indicator gives an indication to the vehicle operator of the status of the driver side front seatbelt. This indicator is controlled by a transistor on the instrument cluster electronic circuit board based upon cluster programming and a hard wired input from the seatbelt switch in the driver side front seatbelt became unit through the seat belt indicator driver circuit. The seatbelt indicator Light Emitting Diode (LED) receives battery current on the instrument cluster electronic circuit board through the fused ignition switch output (run-start) 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 LED only illuminates when it is provided a path to ground by the instrument cluster transistor. The instrument cluster will turn on the seatbelt indicator for the following reasons:
- Seatbelt Reminder Function - Each time the cluster receives a battery current input on the fused ignition switch output (run-start) circuit, the indicator will be illuminated as a seatbelt reminder for about seven seconds, or until the ignition switch is turned to the OFF position, whichever occurs first. This reminder function will occur regardless of the status of the seatbelt switch input to the cluster.
- Driver Side Front Seatbelt Not Buckled - Following the seatbelt reminder function, each time the cluster detects a ground on the seat belt switch sense circuit (seatbelt switch closed = seatbelt unbuckled) with the ignition switch in the Start or ON positions, the seatbelt indicator will be illuminated. The seatbelt indicator remains illuminated until the seat belt switch sense input to the cluster is an open circuit (seatbelt switch open = seatbelt buckled), 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 seatbelt indicator will be turned ON, then OFF again during the bulb check portion of the test to confirm the functionality of the LED and the cluster control circuitry.
The seatbelt switch is connected in series between ground and the seat belt switch sense input to the instrument cluster. The seatbelt switch input to the instrument cluster circuitry can be diagnosed using conventional diagnostic tools and methods. For further diagnosis of the seatbelt indicator or the instrument cluster circuitry that controls the LED, (Refer to ELECTRICAL / INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING).
SHIFT INDICATOR (TRANSFER CASE)
Part Time Indicator
A part time indicator is standard equipment on all instrument clusters. 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 stencil-like 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 it 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 Light Emitting Diode (LED) soldered onto the instrument cluster electronic circuit board. When the exterior lighting is turned On, the illumination intensity of the part time indicator is one-step dimmable, which is adjusted using the panel lamps dimmer control ring on the left multi-function switch control stalk. 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 equipped with the standard 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 in some markets where the Selec-Trac four-wheel drive system is an available option, the part time indicator lights when the transfer case is engaged in the 4 X 4 Part Time or 4 Lo positions. This indicator is controlled by a transistor on the instrument cluster electronic circuit board, and is controlled by a hard wired transfer case switch input to the cluster. The part time indicator Light Emitting Diode (LED) receives battery current on the instrument cluster electronic circuit board through the fused ignition switch output (run-start) circuit whenever the ignition switch is in the ON or Start positions; therefore, the LED will always be OFF when the ignition switch is in any position except ON or Start. The LED only illuminates when it is provided a path to ground by the instrument cluster transistor. The instrument cluster will turn on the part time indicator for the following reasons:
- Transfer Case Switch Input - Each time the cluster detects a ground on the 4WD switch sense (part time) circuit (transfer case switch closed = part time 4WD selected) the part time indicator will be illuminated. The indicator remains illuminated until the 4WD switch sense (part time) input to the cluster is an open circuit (transfer case switch open = part time 4WD not selected), 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 part time indicator will be turned ON, then OFF again during the bulb check portion of the test to confirm the functionality of the LED and the cluster control circuitry.
The transfer case switch is connected in series between ground and the 4WD switch sense (parttime) input to the instrument cluster. The transfer case switch input to the instrument cluster circuitry can be diagnosed using conventional diagnostic tools and methods. For further diagnosis of the part time indicator or the instrument cluster circuitry that controls the LED, (Refer to ELECTRICAL / INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING).
Full Time Indicator
A full time indicator is standard equipment on all instrument clusters, but is only functional on vehicles in some markets where the Selec-Trac four-wheel drive system is an available option. 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 stencil-like 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 it is not illuminated. 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 Light Emitting Diode (LED) soldered onto the instrument cluster electronic circuit board. When the exterior lighting is turned On, the illumination intensity of the full time indicator is one-step dimmable, which is adjusted using the panel lamps dimmer control ring on the left multi-function switch control stalk. 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. On vehicles in some markets where the Selec-Trac four- wheel drive system is an available option, the full time indicator lights when the transfer case is engaged in the 4 X 4 Full Time position. This indicator is controlled by a transistor on the instrument cluster electronic circuit board, and is controlled by a hard wired transfer case switch input to the cluster. The full time indicator Light Emitting Diode (LED) receives battery current on the instrument cluster electronic circuit board through the fused ignition switch output (run-start) circuit whenever the ignition switch is in the ON or START positions; therefore, the LED will always be OFF when the ignition switch is in any position except ON or Start. The LED only illuminates when it is provided a path to ground by the instrument cluster transistor. The instrument cluster will turn on the full time indicator for the following reasons:
- Transfer Case Switch Input - Each time the cluster detects a ground on the 4WD switch sense (full time) circuit (transfer case switch closed = full time 4WD selected) the full time indicator will be illuminated. The indicator remains illuminated until the 4WD switch sense (full time) input to the cluster is an open circuit (transfer case switch open = full time 4WD not selected), 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 full time indicator will be turned on, then OFF again during the bulb check portion of the test to confirm the functionality of the LED and the cluster control circuitry.
The transfer case switch is connected in series between ground and the 4WD switch sense (fulltime) input to the instrument cluster. The transfer case switch input to the instrument cluster circuitry can be diagnosed using conventional diagnostic tools and methods. For further diagnosis of the part time indicator or the instrument cluster circuitry that controls the LED, (Refer to ELECTRICAL / INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING).
SPEEDOMETER
A speedometer is standard equipment in all instrument clusters. The speedometer is located next to the tachometer, 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 electronic circuitry and a fixed 210 degree primary outer scale on the cluster overlay that reads left-to-right either from 0 to 100 mph, from 0 to 110 mph, or from 0 to 180 kph, depending upon the requirements of the market for which the vehicle was manufactured. 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 KPH), followed by the unit of measure for the secondary scale in all lower case letters (i.e.: mph or kph). The speedometer graphics are white (primary scale) and blue (secondary scale) against a black field, 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 white and the blue graphics appear blue. 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 speedometer is serviced as a unit with the instrument cluster.
The speedometer gives an indication to the vehicle operator of the vehicle road speed. This gauge is controlled by the instrument cluster electronic circuit board based upon cluster programming and electronic messages received by the cluster from the Powertrain Control Module (PCM) over the Programmable Communications Interface (PCI) data bus. The speedometer is an air core magnetic unit that receives battery current on the instrument cluster electronic circuit board through the fused ignition switch output (Run-Start) 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:
- Vehicle Speed Message - Each time the cluster receives a vehicle speed message from the PCM it will calculate the correct vehicle speed reading and position the gauge needle at that speed position on the gauge scale. The cluster will receive a new vehicle speed message and reposition the gauge pointer accordingly about every 86 milliseconds. The gauge needle will continue to be positioned at the actual vehicle speed position on the gauge scale until the ignition switch is turned to the OFF position.
- Message Failure - If the cluster fails to receive a speedometer message, it will hold the gauge needle at the last indication for about six 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 six 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 in order to confirm the functionality of the gauge and the cluster control circuitry
The PCM continually monitors the vehicle speed sensor to determine the vehicle road speed, then sends the proper vehicle speed messages to the instrument cluster. For further diagnosis of the speedometer or the instrument cluster circuitry that controls the gauge, (Refer to ELECTRICAL / INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING). For proper diagnosis of the vehicle speed sensor, the PCM, the PCI data bus, or the message inputs to the instrument cluster that control the speedometer, a DRB III scan tool is required. Refer to the appropriate diagnostic information.