The engine coolant temperature gauge has two
intersecting coils wound around a permanent magnet
rotor. Voltage applied to the coils, through fuse 9 (in
driver’s under-dash fuse/relay box), generates a
magnetic field. The magnetic field, controlled by the
coolant temperature sending unit, causes the rotor to
rotate and the gauge needle to move. As the
resistance in the sending unit varies, current through
the gauge coils changes, moving the gauge needle
toward the coil with the strongest magnetic field.

The coolant temperature sending unit’s resistance
varies from about 137 ohms at low engine coolant
temperature to between 30-46 ohms at high
temperature (radiator fan running).

Refer to the Service Manual (Section 10,
Cooling System) for specific tests or
troubleshooting procedures.

Engine Coolant Temperature Gauge (’00-’02)

The engine coolant temperature gauge has two
intersecting coils wound around a permanent
magnet rotor. Voltage applied to the coils, through
fuse 9 (in driver’s under-dash fuse/relay box),
generates a magnetic field. The magnetic field,
controlled by the ECM or PCM causes the rotor to
rotate and the gauge needle to move. As the ECM
or PCM varies the current, current through the
gauge coils changes, moving the gauge needle
toward the coil with the strongest magnetic field.

Refer to the Service Manual (Section 10,
Cooling System) for specific tests or
troubleshooting procedures.

Fuel Gauge

The fuel gauge has two intersecting coils wound
around a permanent magnet rotor. Voltage applied
to the coils, through fuse 9 (in driver’s under-dash
fuse/relay box), generates a magnetic field. The
magnetic field, controlled by the fuel gauge
sending unit, causes the rotor to rotate and the
gauge needle to move. As the resistance in the
sending unit varies, current through the gauge
coils changes, moving the gauge needle toward
the coil with the strongest magnetic field.

The fuel gauge sending unit’s resistance varies
from about 3-5 ohms at full to about 106 ohms at
empty. When you turn the ignition switch to
LOCK (0), the gauge remains at the last reading
until you turn the ignition switch to ON (II) or
START (III) again.

Refer to the Service Manual (Section 11,
Fuel Supply System) for specific tests or
troubleshooting procedures.

Low Fuel Indicator Light

WARNING

Do not smoke while working on the fuel system.
Keep open flame away from the work area.
Drain fuel only into an approved container.

A thermistor is mounted in the fuel tank unit. When
the thermistor is cool, its resistance is very high.
When the thermistor’s temperature increases, its
resistance decreases. Fuel in the fuel tank
transfers heat away from the thermistor fast
enough to keep it cool so the thermistor’s
resistance stays high and the low fuel indicator
light does not come on. When the fuel level drops
below the thermistor, the thermistor’s temperature
increases. With less and less fuel to cool it, the
thermistor’s resistance decreases, eventually
allowing current to flow through the low fuel
indicator light and the thermistor to ground, which
turns on the low fuel indicator light.

Refer to the Service Manual (Section 11,
Fuel Supply System) for specific tests and
troubleshooting procedures.

Speedometer and Odometer

The odometer and speedometer drive circuits
receive pulses from the vehicle speed sensor
(M/T) or PCM (A/T). The pulse rate increases as
the car accelerates. The frequency and duration of
these input pulses are measured and displayed by
the speedometer, odometer, and tripmeter.

Tachometer

The tachometer drive circuit receives pulses from
the PCM or ECM. The solid-state tachometer then
displays these pulses as engine speed. For each
200 pulses per minute from the PCM or ECM the
tachometer displays 100 RPM.

Circuit Index

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80-7

Gauges and Indicators (L4)

Vehicle Speed Sensor (M/T only)

With the ignition switch in ON (II) or START (III),
battery voltage is supplied through fuse 6 (in
driver’s under-dash fuse/relay box) and the
BLK/YEL wire to the vehicle speed sensor. The
sensor is grounded at G101. The speedometer
and other control units in the circuit supply 5 volts
or more to the BLU/WHT wire. The vehicle speed
sensor intermittently grounds the BLU/WHT wire
which generates a pulsed signal in it. The number
of pulses per minute increases/decreases with the
speed of the car.

Refer to the Service Manual (Section 22,
Body Electrical) for specific tests and
troubleshooting procedures.

Circuit Index