For 1990-2009 cars

### Fuel Gauge

The magnetic fields of 2 coils move the pointer of the fuel gauge. The coils are at right angles to each other. Voltage applies to coil F from the IG fuse. The circuit divides at the opposite (ground) side of the coil. One path seeks a ground through coil E to G103. The other path seeks a ground through the variable resistor in the fuel level sender.

When the fuel level is low, the resistance in the fuel level sender is high. Current flows through coil F and coil E to ground at G103 because current always seeks the path of the least resistance. Because the length of the E coil winding is twice the length of the F coil winding, the magnetic field that the E coil generates is twice as strong as the magnetic field that the F coil generates. The magnetic field therefore pulls the pointer to the E position.

As the fuel level increases, the resistance in the fuel level sender decreases. Since current always seeks the path of the least resistance, more current begins to bypass the E coil and travel directly to ground through the fuel level sender. The coil F magnetic field then becomes stronger than the coil E magnetic field, causing the pointer to move toward the F position.

### Engine Coolant Temperature (ECT) Gauge

The magnetic field of 2 coils moves the pointer of the engine coolant temperature (ECT) gauge. The coils are at right angles to each other. Voltage applies to the H coil from the IG fuse. The circuit divides at the opposite (ground) side of the coil. One path seeks a ground through coil C. The other path seeks a ground through the variable resistor in the engine coolant temperature (ECT) sending unit.

The resistance in the ECT sending unit is high when the engine coolant temperature is low. Current flows through the H coil and the C coil to ground at G103 because current always seeks the path of the least resistance. Because the length of the C coil winding is twice the length of the coil H winding, the magnetic filed that coil C generates is twice as strong as the magnetic field that coil H generates. The magnetic field therefore pulls the pointer to the C position.

As the engine coolant temperature increases, the resistance in the ECT sending unit decreases. Since current always seeks the path of the least resistance, more current begins to bypass the C coil and travel directly to ground through the ECT sending unit. The coil H magnetic field then becomes stronger than the coil C magnetic field, causing the pointer to move toward the H position.

### Oil Pressure Indicator

When the ignition switch is in the ON or START position, battery voltage applies through the IG fuse to the oil pressure indicator in the instrument panel cluster assembly. If the engine oil pressure falls below 32 kPa (4.5 psi), the oil pressure switch that is on the engine block closes. The closing of the switch provides a ground path to the oil pressure indicator and the bulb lights.

### Tachometer

The tachometer displays the engine speed in RPM. The noise suppressor filter sends ground pulses from the ignition system to the tachometer. The tachometer responds to the frequency of the ground pulses, which increase with the engine speed. The purpose of the noise suppressor filter within the circuit is to round off pulses and remove the voltage spikes that noise in the circuit causes.