Gauges

Circuit Operation

Engine Coolant Temperature Gauge
The engine coolant temperature gauge consists of two intersecting coils wound around a permanent magnet rotor. When voltage from the C-11 fuse is applied to the coils, a magnetic field is generated. This causes the rotor to rotate and the gauge needle to move. The magnetic field is controlled by the sensor through the PCM. As the resistance in the sender/sensor vanes, current through the gauge coils changes. The gauge needle moves according to the changing magnetic field.

Fuel Gauge
The fuel gauge consists of two intersecting coils wound around a permanent magnet rotor (see engine coolant temperature gauge for operation). The powertrain control module (PCM) monitors the fuel level by the resistance level in the fuel tank unit. The fuel tank unit resistance varies from approximately 80 ohms with the fuel tank full to 290 ohms with the tank empty. The PCM then uses this information to control the fuel gauge.

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 increases with engine speed. Solid-state circuits process these pulses into a signal that causes the gauge needle to move.