RAM 2500 Truck 4WD V8-5.9L VIN Z LDC (1998)
Coolant Temperature Sensor/Switch (For Computer): Testing and Inspection
Fig. 66 Engine Coolant Temperature Sensor
1. Disconnect wire harness connector from coolant temperature sensor.
2. Engines with air conditioning: when removing the connector from sensor do not pull directly on wiring harness. Fabricate an L-shaped hook tool
from a coat hanger (approximately eight inches long). Place the hook part of tool under the connector for removal. The connector is snapped onto
the sensor. It is not equipped with a lock type tab.
Sensor Resistance (OHMS) - Coolant Temperature Sensor/Intake Air Temperature Sensor
3. Test the resistance of the sensor with a high input impedance (digital) volt-ohmmeter. The resistance (as measured across the sensor terminals)
should be less than 1340 ohms with the engine warm. Refer to the Coolant Temperature sensor/Intake Air Temperature sensor resistance chart.
Replace the sensor if it is not within the range of resistance specified in the chart.
4. Test continuity of the wire harness between the PCM wire harness connector and the coolant sensor connector terminals. Repair the wire harness if
an open circuit is indicated.
5. After tests are completed, connect electrical connector to sensor. The sensor connector is symmetrical (not indexed). It can be installed to the
sensor in either direction.
