Temperature Gauge

The magnetic fields of the 2 coils, the 40°C (100°F) coil and the 126.7°C (260°F) coil, move the pointer of the temperature gauge. The magnetic fields interfere with each other, because the 2 coils are at right angles. Battery voltage is available from the GAUGES fuse 4 through CKT 39 (PNK) to the instrument cluster when the ignition switch is in the RUN position or in the START position. Current flowing through the 40°C (100°F) coil places the pointer at the 40°C (100°F) (low temperature) indication. When the current through the 126.7°C (260°F) coil is high, the pointer moves toward the 126.7°C (260°F) (high temperature) indication.

The current passing through the 126.7°C (260°F) coil has 2 paths to ground. Some of the current passes through the fixed resistance of the 40°C (100°F) coil to ground G101 through CKT 451 (BLK/WHT). The remainder of the current goes to ground through the variable resistance of the temperature sensor. The engine coolant temperature gauge sensor produces a resistance of approximately 1305 ohm when the temperature is 40°C (100°F). With this high resistance, more current flows through the 40°C (100°F) coil and the pointer moves toward the 40°C (100°F) indication. The sensor's resistance is approximately 61.9 ohm at 118°C (245°F). With this low resistance, more current passes through the temperature sensor and not the 40°C (100°F) coil. The pointer moves toward 126.71°C (260°F).

A high temperature condition lights the CHECK GAUGES indicator. The setpoint is at approximately 61.9 ohm or 118°C (245°F).

The temperature gauge's accuracy is adequate for normal operator usage.The gauge provides a reasonably accurate indication of the engine coolant temperature. The gauge identifies sudden or long-term changes. The sensing element's response is non-linear over the operating range. This response limits accuracy. The gauge accuracy specification is for 3.5° (angular) at 126.7°C (260°F) and for 7° at 40°C (100°F). Changes in the battery voltage do not affect the gauge accuracy.