Circuit Operation - Gauges Cluster

The operation of an individual indicator is described along with its circuit. Refer to the schematic and text for the circuit that is indicated below each of the indicators.

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

When the tank is low, the resistance of the Sender is low. A large flow of current passes through the E-coil and the Fuel Gage Sender resistor. This moves the pointer towards E on the scale. When the tank is full, the Sender resistance is high. More current now 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 system's battery voltage.

Oil Pressure Gage
The engine oil pressure is displayed by the Oil Pressure Gage. The pointer of the Gage is moved by two coils, and its operation is similar to that of the Fuel Gage.

The Oil Pressure Sender is connected to the junction of the two coils. It has low resistance when the oil pressure is low, and 90 ohms resistance when the oil pressure is high. This changing resistance changes the current flow through the coils. The magnetic fields of the coils move the pointer from low to high.

Temperature Gage
The Temperature gage is also operated by two coils. Battery voltage is supplied to both coils. One is grounded directly and the other is grounded through the Temperature Sender. This has 55 ohms resistance at 127°C (260°F) (hot coolant) and its resistance becomes greater at low temperatures. It is approximately 1400 ohms at -18°C (0°F). This causes the current through the Sender and one coil to increase as the coolant temperature increases. This moves the pointer.

Voltmeter
The Voltmeter shows the battery voltage. If the generator output is high, low or 0 volts, the BATT indicator which monitors generator output by monitoring the differences in voltage between circuits 25 and 39 will come on.

Brake And 4WAL Indicators
Refer to Antilock Brake System. Antilock Brakes / Traction Control Systems

Batt Indicator
Refer to Charge Lamp/Indicator Charge Lamp/Indicator

RH/LH Turn Indicators
Refer to Lighting and Horns for Exterior Lights. Description and Operation

High Beam Indicator
Refer to Headlamp. Lighting and Horns

Safety Belt Indicator
Refer to Audible Warning Device. Audible Warning Device

Daytime Running Lamps Indicator
Refer to Daytime Running Lamp. Daytime Running Lamp