Test E: Temperature Warning Indicator Flickers & Gauge Reads Fully Hot

WARNING: This page is about a different car, the 2002 Ford RV Cutaway, 2002 Ford F450 Super Duty, 2002 Ford Econoline, 2002 Ford E450 Super Duty, and 2002 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Engine Coolant Temperature (ECT) sender Black 2-pin harness connector C1061 (except diesel) is located on heater outlet elbow on 4.2L gasoline engine or on top of engine on all other non-diesel engines. Engine Coolant Temperature (ECT) sender 2-pin harness connector C1276 (diesel) is located in left front of engine compartment. For purposes of this test, both connectors will be referred to as ECT sender 2-pin harness connector.

NOTE: Ensure coolant level is correct. Verify ECT sender 2-pin harness connector is securely connected.

Turn ignition switch to ON position. Observe temperature gauge and indicator while wiggling ECT sender wiring harness and 2-pin harness connector (Red/White and Yellow/Red wires). If temperature gauge and indicator remain steady, go to next step. If gauge fluctuates and/or indicator flickers, repair open in Red/White and/or Yellow/Red wire(s). See WIRING DIAGRAMS . Retest system operation.
Turn ignition switch to LOCK position. Disconnect ECT sender 2-pin harness connector. Connect a 10-amp fused jumper wire between ECT sender 2-pin harness connector terminals. Turn ignition switch to ON position. Temperature gauge should read fully hot with jumper wire installed and fully cold with jumper wire removed. If gauge reads as specified, replace ECT sender. See ENGINES article. Retest system operation. If gauge does not read as specified, go to TEST D: TEMPERATURE GAUGE INACCURATE .