Instrument Cluster / Carrier: Description and Operation

CLUSTER ILLUMINATION
The Cluster Illumination Lamps voltage is supplied by the Panel Dimmer Switch through the ILLUM Fuse 21 and the GRY (8) wire. Ground for the lamps is provided through the BLK (150) and BLK/WHT (151) wires.

SPEEDOMETER
The Speedometer receives an A/C output signal from the Powertrain Control Module (PCM) through the DK GRN (389) wire or the Vehicle Control Module (VCM) through the DK GRN/WHT (817) wire and converts this to an analog (needle-type) display of vehicle speed.

FUEL GAUGE
Voltage to the Fuel Gauge is supplied through the PNK (39) wire with the Ignition Switch in START or RUN. The movement of the Fuel Gauge needle is controlled by current flowing through two coils in the Gauge. This movement creates magnetic fields in the coils. The amount of current flowing through each coil is controlled by the Fuel Level Sensor W/ Fuel Pump. Voltage from the PNK (39) wire is applied to one end of the EMPTY (E) coil. The other end of the E-coil is connected to the FULL (F) coil, Fuel Level Sensor W/ Fuel Pump and PNK (30) wire.

When the Fuel Tank is empty the resistance of the Fuel Level Sensor WI Fuel Pump is low (one ohm). This allows more current to flow through the E-coil and the Fuel Level Sensor W/ Fuel Pump resistor, and the magnetic field in the E-coil pulls the pointer toward E on the Fuel Gauge.
When the Fuel Tank is Full, the resistance of the Fuel Level Sensor W/ Fuel Pump is high (88 ohms). This allows more current to flow through the F-coil to ground, and the magnetic field in the F-coil pulls the pointer toward F on the Fuel Gauge.

OIL PRESSURE GAUGE
The Oil Pressure Gauge operates the same as the Fuel Gauge. The resistance controlling the current flow through the coils (High coil and Low coil) is provided by the Fuel Pump Switch and Engine Oil Pressure Gauge Sensor through the TAN (31) wire. With no oil pressure, the resistance of the sender is low (one ohm). At 275 kPa (40 psi), the resistance is high (44 ohms).

ENGINE COOLANT TEMPERATURE GAUGE
The Engine Coolant Temperature Gauge also operates the same as the Fuel Gauge and Oil Pressure Gauge. Resistance controlling the coils (Hot coil and Cold coil) is provided by the Engine Coolant Temperature Gauge Sensor through the DK GRN (35) wire. However, with a coolant temperature of 40° C (104° F), resistance of the sender is high (1365 Ohms). With a coolant temperature of 125° C (257° F), resistance of the sender is low (55 Ohms).

VOLTMETER
The Voltmeter indicates battery voltage with the Ignition Switch in RUN and the engine not running. With the engine running, the Voltmeter indicates generator output.

INDICATOR LAMPS
Voltage to the BRAKE, SERVICE ENGINE SOON, CHECK GAUGES, Battery, DAYTIME RUNNING LAMPS, ANTILOCK Brake, AIR BAG, and SHIFT Indicators is provided through the GAUGES Fuse 4 and the PNK (39) wire with the Ignition Switch in Start or Run. Ground for the Indicators is provided by various components in the vehicle.

Voltage to the Right Turn, Left mm, High Beam and Safety Belt Indicators is provided by various components in the vehicle. Ground is provided to these indicators through the BLK (150) wire.

BRAKE INDICATOR
Ground to light the BRAKE Indicator is provided in one of four ways. When the Ignition Switch is turned to Run, the Brake Pressure Modulator Valve (BPMV) provides a ground to the indicator for about two seconds through the TAN/WHT (33) wire. This indicates the Four Wheel Antilock Brake System (4WAL) is operating properly. If a malfunction occurs in the 4WAL system of the hydraulic portion of the Antilock Brake System, the BRAKE Indicator will light.

The BRAKE Indicator will light when the parking brake is set. This closes the Park Brake Warning Switch providing a ground to the BRAKE Indicator.
If a brake hydraulic circuit loses pressure, the Brake Pressure Warning Switch closes, providing a ground to the BRAKE Indicator.

ANTI LOCK BRAKE INDICATOR
Ground to the ANTILOCK Brake Indicator is supplied by the Brake Pressure Modulator Valve (BPMV) if a problem exists within the electronics of the Four Wheel Antilock Brake System.

BATTERY INDICATOR
Ground to the Battery Indicator is controlled by the lamp driver circuit in the Generator. The Battery Indicator will light whenever undervoltage, overvoltage or a stopped Generator is detected by the lamp driver circuit.

SERVICE ENGINE SOON INDICATOR
The SERVICE ENGINE SOON Indicator will light if a problem is detected by the PCM or VCM with the engine running and the vehicle moving.

CHECK GAUGES INDICATOR
The CHECK GAUGES Indicator lights to alert the driver to a low oil pressure or high coolant temperature condition. The signals from the Engine Coolant Temperature Gauge Sensor and the Fuel Pump Switch and Engine Oil Pressure Sensor are monitored by the Check Gauges Lamp Driver which is part of the Temperature Gauge. The lamp driver controls the ground to the CHECK GAUGES Lamp mounted in the Instrument Cluster.

SHIFT INDICATOR
On vehicles with a manual transmission, the SHIFT Indicator lights when the vehicle should he shifted to the next higher gear for better fuel economy. The PCM(VCM uses engine data such as rpm, vehicle speed and intake manifold vacuum to compute an efficient shift point-The PCM/VCM provides a ground to light the SHIFT Indicator through the TAN/BLK (456) wire.

TURN INDICATORS
Voltage to the turn indicators is provided by the Turn Signal Switch (part of the Multi-Function Switch) or Hazard Switch. Voltage to the Left Turn Indicator is supplied through the LT BLU (14) wire. The Right Turn Indicator is supplied voltage through the DK BLU (15) wire.

HIGH BEAM INDICATOR
Voltage to the High Beam Indicator is provided by the WHT (629) wire with the Headlamps On and the Headlamp Dimmer Switch in HI position.

SAFETY BELT WARNING INDICATOR
The Safety Belt Warning Indicator is supplied a ground by the Seat Belts & Ignition Key & Lamps Alarm when the Ignition Switch is first turned to Run.

TACHOMETER DISPLAY
The Tachometer Display shows engine revolutions per minute (RPM). The Tachometer is connected to the WHT (121) wire.

PRNDL DISPLAY
The PRNDL display shows the current gear selection. The PRNDL display receives inputs from the Park(Neutral Position and Backup Lamp Switch. The PRNDL inputs provide the Instrument Cluster with a code of logic (1's or 0's) in accordance with the Gear Selector Position Table. Less than 5 ohms in the table corresponds to a logic 0 and infinite "OL" corresponds to a logic "1".