Temperature Gauge: Description and Operation
An engine coolant temperature gauge is standard equipment on all instrument clusters. This gauge is located on the right side of the instrument cluster,
just right of the tachometer. The gauge consists of a movable gauge needle or pointer controlled by the instrument cluster circuitry and a fixed 90 degree
gauge scale on the cluster overlay that reads left-to-right from C (or Cold) to H (or Hot) for all vehicles except SRT8. On SRT8 the scale reads from 80
° C to 120° C in markets where a metric instrument cluster is specified, or from 185° F to 245° F in all other markets. An International Control and
Display Symbol icon for Engine Coolant Temperature is located on the cluster overlay, directly above the hub of the gauge needle.
On all vehicles the engine coolant temperature gauge graphics are gray and white against a black field except for two red graduations at the high end of
the gauge scale.
In all Laredo vehicles, the gauge graphics are clearly visible within the instrument cluster in daylight. When illuminated from behind by the panel lamps
dimmer controlled cluster illumination lighting with the exterior lamps turned ON, the white text and graphics still appear white, the gray graphics still
appear gray and the red graphics still appear red. The red gauge needle has internal optical illumination. Gauge illumination is provided by Light
Emitting Diode (LED) units soldered onto the instrument cluster electronic circuit board.
In all vehicles except Laredo, the gauge graphics are nearly invisible within the instrument cluster in daylight while the ignition switch is in the OFF
position. When the ignition is turned ON the gauge is illuminated from behind at full brightness by the cluster illumination lighting. The white text and
graphics still appear white, the gray graphics still appear gray and the red graphics still appear red. The white gauge needle has internal optical
illumination. With the exterior lamps turned ON, the cluster illumination lighting is panel lamps dimmer controlled. Gauge illumination is provided by
LED units soldered onto the instrument cluster electronic circuit board.
The engine coolant temperature gauge is serviced as a unit with the instrument cluster.