Chrysler Full-Size Trucks 1997-2000 Repair Guide



This section covers sending units and sensors which are designed to provide the driver with information on vehicle condition.

Instrument panels contain a number of indicating devices (gauges and warning lights). These devices are composed of two separate components. One is the sending unit, mounted on the engine or other remote part of the vehicle, and the other is the actual gauge or light in the instrument panel.

Several types of sending units exist. However, most can be characterized as being either a pressure type or a resistance type. Pressure-type sending units are normally on-off in operation, completing or breaking a circuit to operate a warning light. Resistance-type sending units use variable resistance to control the current flow back to the indicating device like a gauge to indicate variations of pressure or temperature. Both types of sending units are connected in series by a wire to the battery (through the ignition switch). When the ignition is turned ON , current flows from the battery through the indicating device and on to the sending unit.