Can anyone tell me what this is?

[99 EXP]

I have a 1999 Expedition E.B. with a 5.4. The motor was rebuilt (not by me) but I noticed the plug (circled in the pic) with no harness to be found. I've looked everywhere my gauntlet hands fit but no luck. What sensor is it and more importantly, what color are the wires connected to the harness. I will locate the wires from the ECU and wire them directly. Thanks!

 

[Thermo]

99Exp, that is the engine coolant temp sensor as I recall. Looking at the intake, you also have a 97 intake, not a 99+ intake. Just thought you might want to know.

 

[SkyJumper]

That there looks to be the engine coolant temperature sensor. Wire colors should be red/white and yellow/red. The harness for it should be branched off that main harness you have your hands on.

 

[99 EXP]

Thanks for the replies. If the intake is off of an earlier year (97-98), or the motor is an earlier year, how do I connect the sensor if the harness is from a 99 and does not have the ECT sensor? I'm getting around 12 mpg with it unplugged and it's throwing the code. Thanks again!