Base Cluster

CIRCUIT OPERATION

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.

FUEL GAUGE
The pointer of the Fuel Gauge is moved by the magnetic fields of two coils. The coils are at right angles to each other. Battery voltage is applied to the E coil, and the circuit divides at the opposite end of this coil. One path continues to ground through the F coil. Another goes to ground through the variable resistor of the Fuel Level Sender.

When the tank is low, the resistance of the Fuel Level Sender is low. A large flow of current passes through the E coil and the Fuel Level Sender resistor. This pulls the pointer towards E on the scale. When the tank is full, the Fuel Level Sender resistance is high. More current now flows through the F coil, moving the pointer to F on the scale.

With two coils operating the pointer, the Fuel Gauge is not affected by changes in the voltage of the system.

COOLANT TEMPERATURE GAUGE
The Coolant Temperature Gauge is also operated by two coils. Battery voltage is applied to both coils. One is grounded directly and the other is grounded through the Coolant Temperature Sender. The Coolant Temperature Sensor has 55 ohms resistance at 260°F (125°C) and its resistance increases at lower temperatures. Resistance is approximately 1365 ohms at 100°F (37°C). This causes the current through the Coolant Temperature Sender and one coil to increase as the coolant temperature increases and moves the pointer.

"OIL" PRESSURE INDICATOR
The "OIL" Pressure Indicator comes on to warn the driver when the engine oil pressure is low. Battery voltage is applied to one side of the bulb. A ground path is provided by the Fuel Pump/Oil Pressure Switch. It closes when the oil pressure is below 26 kPa (4 psi) and the Indicator bulb lights. After the Engine starts and normal oil pressure builds up, the Fuel Pump/Oil Pressure Switch opens. The "OIL" Pressure Indicator goes out.

SPEEDOMETER AND ODOMETER
The Vehicle Speed Sensor (VSS) generates a signal that indicates the speed of the solid state ECM to supply inputs to the Cruise Control Module, Speedometer and Odometer.

The Vehicle Speed Sensor is mounted in the Transaxle. A magnet rotates near a coil, producing voltage pulses in the coil. The frequency of the AC voltage coming from this coil depends on the vehicle speed. The VSS sends pulses to the ECM at the rate of 40,000 pulses per mile.

The ECM takes the voltage pulses from the sensor and uses them to close a solid state output switch. The output terminal is switched to ground at a rate that is proportional to the speed of the vehicle. The Speedometer and Odometer are switched at 4,000 pulses per mile.

"LOW COOLANT" INDICATOR
The "LOW COOLANT" indicator receives battery voltage with the ignition Switch in "RUN," "BULB TEST" or "START." The indicator is grounded by the Coolant Level Switch with the coolant level in the Coolant Reservoir below a minimum recommended level.