Mystery wires

[Claude]

I am trying to install a second water sensor and gauge to my 411 S1 to see if the engine is overheating or the Smiths gauge or engine block sensor is lying. In addition to the standard sensor in the block with a green wire, there is a second T pipe coming out of the block with a radiator hose on one part of the T and some sort of sensor with an aftermarket fat wire that runs into an aftermarket junction and on the other side is a smaller wire that goes into the Bristol wiring loom, suggesting it is original. The smaller wire appears in its dirty form to be white, although it could be faded yellow or striped. I was unable to find anything on the 12 wiring diagrams for the 411 that looked like a likely candidate.

It would be easy to remove that sensor and replace it with my test unit, but before I do, I would like to know what it goes to. There also is a sensor on the radiator that I believe turns on the Kenlow fans, so I don't think it has to do with that.

My questions:

(a) does anyone know what it is, what it drives and where it goes?
(b) if not, does anyone with a 411 have such a T pipe fitting that looks like it is iron from a plumbing supply store? I may have an add-on orphan that is redundant.
(c) any other thoughts on how to easily install the test sensor?

My plan is to leave the second sensor and gauge in permanently, either installing it in the glove or in the engine compartment, since no doubt this concern will arise again.

Claude

[Kevin H]

Claude,
Any chance of a photo?
Kevin