I'm finishing reassembly after a clutch job, and I noticed that this connector has nothing connected to it. I didn't notice it on disassembly, and it doesn't look like it would have been necessary to disconnect it, and I can find any dangling wire that looks like it would connect there, but I thought I'd check in here to see if anyone knows what specifically this is, and if it should be connected.

 

I believe that earlier N18 engines had that Temperature Sensor. It should plug into the Thermostat wires.

 

If its has the newest thermostat installed and pigtails add on it will be bypassed. Looks like you have it?

https://www.northamericanmotoring.co...ntryman-s.html

PM me your vin.

 

I did more research, and it points to that being where a piloted oil pump solenoid would connect if I had one, but I don't, so it's expected that that will not have anything connected to it. Does that sound right to you? Is that something that you could confirm from my VIN?

 

Its part of the coolant and thermostat system and it unconnected and no CEL, you have a pigtail update and updated thermostat. So it just sits their unpluged.

 

The oil pump solenoid woiuld nbe inside the oil pan, that hose connects to your thermostat as mentioned. On the earlier N18 models, the Thermostat has an external temp sensor (which is in your picture). The newer models bypass it as mentioned by @ECS Tuning