Magnetic fields of two coils moves the pointer of the fuel gauge. The coils are at right angles to each other. Battery voltage is applied to the E-coil (empty) and the circuit divides at the opposite end of the coil. One path continues to ground through the F-coil (full). Another path goes to ground through the variable resistance of the level sensor in the fuel pump and sender (Gasoline) or the fuel gauge sender (Diesel) with single fuel tank vehicles.

The fuel pump balance module averages the resistance for vehicles with two fuel tanks. When the tank is low, the resistance of the level sensor is low. A large current flow passes through the E-coil and the pointer moves toward E on the fuel gauge. When the tank is full, the level sensor resistance is high, and less current passes through the E-coil, and the pointer moves toward F on the scale. With two coils operating the pointer, the fuel gauge is not affected by changes in the systems battery voltage.

For single fuel tank vehicles, the fuel gauge includes the following functions:

For dual fuel tank vehicles, the fuel pump balance module does the following functions:

When the level in the front tank increases to about two gallons greater than the rear tank, the secondary fuel pump stops. This then empties the rear tank first.

The oil pressure gauge displays the engine oil pressure. Current flow through two coils moves the pointer of the gauge and is similar in operation to the fuel gauge. The fuel pump oil pressure switch and sender senses engine oil pressure.

The oil sender has a low resistance (approximately 0 ohms) when the oil pressure is low (0 psi), and a high resistance (approximately 90 ohms) when the oil pressure is high (80 psi).

The temperature gauge displays the engine coolant temperature. Current flow through two coils moves the pointer of the gauge and is similar in operation to the fuel gauge. The engine coolant temperature sender has a low resistance at higher temperatures. The sender has a resistance of approximately 49.5 ohms at 123°C (260°F).

The sender resistance increases at lower temperatures and is approximately 1305 ohms at 47°C (100°F). This causes the current through the sensor to increase as the coolant temperature increases and the temperature gauge pointer then moves toward the hot end of the gauge.

The voltmeter measures the electrical system's voltage when the ignition switch is in the RUN or START position. The voltmeter measures battery voltage when supplied to the instrument cluster.

With the engine running, the normal reading is between 12-16 volts. The indication may decrease to 9.5 volts in cold weather with the engine stopped.

The low coolant level indicator only illuminates to warn the operator when the radiator has a low coolant level. Battery voltage is applied to the low coolant level indicator module when the ignition switch is in the RUN or START positions. The low coolant level indicator module monitors the resistance of the low coolant level sensor. The level sensor has a high resistance of 50,000 ohms or more when the coolant level is low. This is the setpoint at which the low coolant level indicator module grounds CKT 68 (YEL/BLK) in order to illuminate the low coolant lamp.

An increasing coolant level can reduce this resistance to less than 10,000 ohms. The lamp turns off below approximately 50,000 ohms.

The vehicle speed sensor (VSS) produces voltage pulses of frequency in proportion to vehicle speed. The vehicle speed sensor (VSS) buffer (Diesel) or the vehicle control module (VCM) (Gasoline) processes this signal in order to produce a voltage pulse signal to the speedometer and the odometer.

The tachometer displays the engine speed in revolutions per minute (RPM). Voltage pulses are taken from the ignition control module (ICM) (Gasoline) or the generator (Diesel) and sent to the tachometer. Solid state circuits convert the pulse frequency in order to move the pointer of the tachometer.

The PRNDL indicator shows the gear selection for an automatic transmission (AT). The PRNDL indicator receives coded input through four wires from the transmission range (TR) selector (part of the park/neutral position (PNP) switch).

A gear selection light emitting diode (LED), for example Reverse (Rev), illuminates depending on which combination of the four wires to the PRNDL indicator are grounded.

The indications are separate from the transmission's inputs to the vehicle control module (VCM) (Gasoline) or the powertrain control module (PCM) (Diesel).

The check gauges lamp illuminates when the engine oil pressure is low or the engine coolant temperature is high.

The instrument cluster's check gauges lamp driver solid state logic monitors the input signals to the oil pressure gauge and the temperature gauge.

When the ignition switch is turned to the RUN or the START position, the check gauges lamp driver grounds the check gauges lamp when either of the input signals exceed the setpoint. this cause the lamp to illuminate. The lamp is normally illuminated when the ignition switch is turned to the RUN position. The lamp turns off when the engine is started and the oil pressure increases above the setpoint.