Base

COOLANT TEMPERATURE GAGE

The Coolant Temperature Gage is 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. This has 55 ohms resistance at 260°F (hot coolant) and its resistance increases at lower temperatures. Resistance is approximately 1365 ohms at 100°F. This causes the current through the Sender and one coil to increase as the coolant temperature increases. This moves the pointer.

FUEL GAGE

The pointer of the Fuel Gage is moved by the magnetic field 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. The other path grounds through the variable resistor of the Fuel Gage Sender.

When the tank is low, the resistance of the sender is low (0 ohms). A large flow of current passes through the E coil and the Fuel Gage Sender resistor. This moves the pointer toward E on the scale. When the tank is full, the sender resistance is high (90 ohms). More current flows through the F coil, moving the pointer toward F on the scale.

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

COOLANT TEMPERATURE INDICATOR

The Coolant Temperature Indicator warns of high coolant temperature. The Coolant Temperature Indicator receives battery voltage through the CLUST Fuse in RUN. The Indicator Control Unit receives an input signal from the Coolant Temperature Sender. when the Coolant Temperature Sender resistance is low, the Indicator Control Circuit grounds the Coolant Temperature Indicator, which lights to warn the driver. when the Coolant Temperature Sender resistance is high, the Indicator Control Circuit removes the ground and the indicator goes out.

LOW FUEL INDICATOR

The Low Fuel Indicator warns of a low fuel level. The Low Fuel Indicator receives battery voltage through the CLUST Fuse in RUN.The Indicator Control Circuit receives an input signal from the Fuel Tank Sender. When the Fuel Tank Sender resistance is low, the Indicator Control Circuit grounds the Low Fuel Indicator, which lights to warn the driver. When the Fuel Tank Sender resistance is high, the Indicator Control Circuit removes the ground and the indicator goes out.

OIL PRESSURE INDICATOR

The Oil Pressure Indicator goes on to warn of low oil pressure when the Fuel Pump/Oil Pressure Switch/Sender is closed. The Fuel Pump/Oil Pressure Sender/Switch is closed when the oil pressure falls below 27 kpa (4 PSI). When the engine is initially cranked, oil pressure is below 27 kpa, so the Fuel Pump/Oil Pressure Switch/Sender is closed, and the Oil Pressure Indicator goes on momentarily as a Bulb Test. The Fuel Pump/ Oil Pressure Switch/Sender opens as soon as the oil pressure is above 27 kpa (4 PSI) and the Oil Pressure Indicator goes off.