Gauges

Circuit Description
When the ignition switch is in the ON or START position, battery voltage is applied to the gauges (speedometer, tachometer, fuel gauge and engine coolant temperature gauge) from fuse 28.

Speedometer
The speedometer drive circuit receives pulses from the vehicle speed sensor(VSS). The pulse rate increases as the car accelerates. The frequency and duration of these input pulses are measured and displayed by the speedometer.

Tachometer
The tachometer displays engine speed in rpm. Voltage pulses are taken from the ignition system and sent to the tachometer. The tachometer responds to the frequency of the voltage pulses, which vary according to engine speed. The PCM process these pulses into a signal that causes the gauge needle to move.

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. The magnetic field controlled by the fuel gauge sender causes the gauge needle to move. As the resistance in the sender varies, current through the gauge coils changes. When the fuel level is below the thermistor, the resistance of thermistor drops, providing a ground for the low fuel indicator bulb.

Engine Coolant Temperature Gauge
The pointer of the engine coolant temperature gauge is moved by the magnetic field of two coils. The coils are at right angles to each other. The magnetic fields controlled by the engine coolant temperature sender cause the gauge needle to move. As the resistance in the sender varies, current through the gauge coils changes.