78 Volare Slant-6 Temp. Gauge...Sender??

On a 78 Volare with a slant six, where exactly is the water temperature sender?............The gauge isn't working, and I would assume to check the sender first..........AND, I'm not familiar with the gadget mounted on the radiator that looks a bit like an A/C pressure switch, with a couple of hoses coming off it.............

Can someone lend some aid? What's the gadget, and where's the sender???

Thanks.................. Doc :director::toothy7:

The gadget is an emission part and the sender should be at the top front of the head.

Chuck

im not positive but I think 75 & ^ heads had the sender in the front of the head between the manifolds and the valve cover, if im correct I think their is only one wire comming off it. be careful cuz their is also another thermal vaccum switch up thier with a few hoses comming off(I have a 75 dart and I think it is all in the same location)