Gauges

Circuit Description
Battery voltage is supplied to the gauges from fuse 18 when the ignition switch is in ON or START. The details of each gauge follows:

Speedometer
With the ignition switch in ON and START; the speedometer drive circuit receives pulses from the vehicle speed sensor. 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 by the ECM. The tachometer responds to the frequency of the voltage pulses, which vary according to engine speed.

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. Battery voltage is applied to the coils through fuse 18, generating the magnetic fields. The magnetic fields, 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. The fuel gauge sender's resistance varies from about 95 Ohm at empty to 7 Ohm when full.

Engine Coolant Temperature Gauge
The pointer of the engine coolant temperature gauge is moved by the magnetic fields of two coils. The coils are at right angles to each other. Battery voltage is applied to the coils through fuse 18, generating the magnetic fields. 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. The engine coolant temperature sender's resistance varies from about 157 Ohm at 55 °C to 24 Ohm at 110 °C.