TL L5-2451cc 2.5L SOHC MFI (1997)
Temperature Gauge: Description and Operation
The Engine Coolant Temperature (ECT) gauge has two intersecting coils wound around a permanent magnet rotor. Voltage applied to the coils, through
fuse 1, generates a magnetic field. The magnetic field controlled by the ECT 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 pulling the gauge needle toward the coil with the stronger magnetic field.
The fuel gauge works the same way.
The resistance of the sending unit for the ECT gauge varies from about 137 ohms at low engine temperature to between 46-30 ohms at high temperature
(radiator fan running).
The resistance of the sending unit for the fuel gauge varies from about 3.5-5 ohms at full, to about 105-108 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.
