sensor ID help

[gustycrosswinds]

Greetings,
I've got the 4d55t with AC and I found a sensor that doesn't have a wire attached to it.
The switch is on a coolant flange coming out of the engine, driver's side, the coolant hose goes from there into the top of the radiator. It is close to the injectors and the temperature switch for engine temp.
It looks like another temperature switch, could it be for the AC or related to the glow plugs?
Any insight would be helpful.

[MrPaco]

Any chance your truck has an auto transmission? There's an extra temp sensor that activates the overdrive on auto trucks (I learned that here while troubleshooting a sensor issue )

[geezer101]

Any chance your truck has an auto transmission? There's an extra temp sensor that activates the overdrive on auto trucks (I learned that here while troubleshooting a sensor issue )

I was thinking the same, or someone had swapped intake manifolds...

[gustycrosswinds]

It is a manual, not sure if it ever had an auto in it.