Mercury F68Z-10884-AA Temperature Sender Assembly

The coolant temperature indicator system includes a dash warning light or gauge and a temperature sending unit on the engine. Four-cylinder and post-2008 V6 models use a Cylinder Head Temperature sensor, while pre-2009 V6 models use an Engine Coolant Temperature sensor. These sensors inform the Powertrain Control Module and function as the coolant temperature sending unit. If overheating is indicated, check the coolant level and wiring harness connectors. The indicator light should come on when the ignition is turned to START and go out once the engine starts, unless the engine overheats. If the light doesn't behave as expected, it could be due to a faulty bulb, ignition switch, circuit, grounded wire, or sending unit. Ensure the coolant is correctly mixed to activate the sending unit.