RAM 3500 Truck 2WD L6-359 5.9L DSL Turbo VIN D FI (1998)
Coolant Temperature Sensor/Switch (For Computer): Testing and Inspection
Fig 9 ECT Sensor
To perform a complete test of the Engine Coolant Temperature (ECT) sensor and its circuitry, refer to Powertrain Management/Computers and Controls.
To test the sensor only, refer to the following:
1. The ECT sensor is equipped with a 9 inch long jumper harness. This harness connects the ECT sensor to the main engine wiring harness. The end
of the harness is located near the top of the fuel filter. It is used for sensor tests. Disconnect jumper harness connector from main engine wiring
harness.
ECT Sensor Resistance -- Ohms
2. Test resistance of sensor with a high input impedance (digital) volt-ohmmeter. The resistance (as measured across the jumper harness terminals)
should be as shown in ECT SENSOR RESISTANCE (OHMS) chart. Replace sensor if it is not within range of resistance specified in chart.
3. Test continuity of the wire harness between the PCM wire harness connector and the ECT sensor connector terminals. Refer to Group 8, Wiring
for terminal/cavity locations. Repair the wire harness if an open circuit is indicated.
4. After tests are completed, connect jumper harness.