Digital Cluster

See the circuit referred to for the complete operation of an indicator and other components that work with it. Only the indicators that do not appear in other schematics are described in this section.

OIL INDICATOR

The Oil Indicator bulb is permanently grounded at G200. The Solid State Module inside the Instrument Cluster gets a signal from the Fuel Pump Switch/Oil Pressure Sender. If the resistance in the sender decreases, indicating low oil pressure, the Cluster will provide voltage to the Oil Indicator, causing it to light.

COOLANT TEMPERATURE INDICATOR

The Coolant Temperature Indicator comes "ON" to warn the driver of high coolant temperature.
With the Ignition Switch in "RUN," "BULB TEST" or "START," voltage from Fuse 17 is applied to the Coolant Temperature Indicator. In "BULB TEST" or "START," the lamp is grounded through the Ignition Switch so that the bulb can be tested. In "RUN," the current path is completed through the Coolant Temperature Switch/Sender. The Coolant Temperature Switch/Sender contains a switch which closes when the coolant temperature exceeds 126°C (258°F) causing the lamp to come "ON."

FUEL GAGE

With the Ignition Switch in "RUN," "BULB TEST" or "START," voltage is applied from Fuse 17 to the Fuel Gage. The Fuel Gage pointer is controlled by varying the Fuel Gage Sender resistance. Voltage is applied from Fuse 17 to the Empty coil of the Fuel Gage and divides into two paths: 1) through the Fuel Gage Sender to ground, and 2) through the Full coil to ground. The Gage pointer is controlled by changes of the sender resistance. When the Fuel Gage resistance decreases, more current flows through the sender and the Empty coil. At the same time, the current through the Full coil decreases.
With two coils operating the pointer, the gage is not affected by changes in the voltage of the system.

COOLANT TEMPERATURE GAGE

The Coolant Temperature Gage applies voltage from CKT 135 to the Coolant Temperature Switch/Sender. The Coolant Temperature Switch/Sender contains a variable resistor. At 40°C (100°F) the resistance is approximately 1365 ohms and at 125°C (260°F) the resistance is approximately 55 ohms. As the resistance of the Coolant Temperature Switch/ Sender decreases, the Coolant Temperature Gage senses a smaller voltage drop across the Coolant Temperature Switch/Sender, indicating higher coolant temperature. As the resistance of the Coolant Temperature Switch/Sender increases, the Coolant Temperature Gage senses a larger voltage drop across the Coolant Temperature Switch/Sender, indicating a lower coolant temperature.

"LOW OIL LEVEL" INDICATOR

The Low Oil Indicator ground is controlled by the Low Oil Module. To check for a low oil condition, the Low Oil Module looks for a ground through the Oil Level Switch after the Ignition Switch has been turned to "OFF" or "LOCK".
The Low Oil Module checks for a low oil condition 32 minutes after the Ignition Switch is turned to "OFF" or "LOCK", if the previous ignition cycle was less than 12 minutes. If the previous ignition cycle was longer than 12 minutes, the Low Oil Module checks for a low oil condition 3 minutes after the Ignition Switch is turned to "OFF" or "LOCK".
When the Low Oil Module loses the ground through the Oil Level Switch (Oil Level Switch open indicating low oil level) the Low Oil Module grounds the Low Oil Indicator for the duration of the next ignition cycle.
The Low Oil Module grounds the Low Oil Indicator for a bulb test when the Ignition Switch is turned to "RUN" during the next ignition cycle. The bulb test takes four to five seconds.

DIGITAL SPEEDOMETER

The Digital Speedometer Display uses vacuum fluorescent displays to show vehicle speed only. With the Ignition Switch in "RUN", current flows from Fuse 13 to the Instrument Panel Cluster connector C1. For 3 seconds the entire display lights up to check all segments. After the segment check, only the vehicle speed data is displayed.

"DOOR OPEN" INDICATOR

B+ is applied at all times to connector C2 terminal "B11", which powers the "DOOR OPEN" Indicator. CKTs 156 and 146 connect this indicator to Jamb Switches, the Tailgate Ajar Switch and I/P Dimmer Switch. When any of these switches close to ground, the "DOOR OPEN" Indicator comes "ON".