Broken sensor?

While installing a new head gasket in my son's '86 B2000 I discovered this item that looks like a sensor with the electrical connection broken off. It is under the intake manifold even with the back edge of the carb. I'll try to get a better picture that can bee seen...

There is a lead that looks like a temp sensor, but it doesn't fit into the opening of the sensor in the picture. [edit] I figured out that the lead was wrapped around part of the sensor, and then encased in plastic...

I assume one of these is the reason the temp gauge doesn't work?

The joys of buying a used truck w/o a warranty...

Purchased wt608 sending unit...buzz... much smaller than the one in the bottom of the manifold. WT608 sending unit is about 12mm across with an 8mm x .7 thread. Unit in manifold is 19mm across with about (guessing) 14mm thread.

Looks like the temp sensor to me... that's what it looks like when it pulls out of the threaded brass.

I believe it turned out to be a TS15. Not what an 86 should have. but now the gauge works.