Engine Coolant Temperature (ECT) Sending Unit Test

Turn ignition switch to OFF position. Ensure coolant level is correct and cooling system is operating properly. On 3.5RL, remove engine cover. On all models, disconnect Yellow/Green wire from Engine Coolant Temperature (ECT) sending unit. Sending unit is located in middle of engine.
Using a DVOM, measure resistance between ECT sending unit terminal and ground. On 3.2TL, with engine coolant at about 133°F (56°C), resistance should be about 137 ohms. On 3.2TL, with engine coolant at 185-212°F (85-100°C), resistance should be about 30-46 ohms. On 3.5RL, with engine coolant at about 122°F (50°C), resistance should be about 226 ohms. On 3.5RL, with engine coolant at 239°F (115°C), resistance should be about 26.4 ohms. If resistance is considerably different than specified, replace ECT sending unit.