No temp reading on the panel

[mikeyfev1]

Everything seems to be working on my 1985 300D dashboard except the coolant temp meter; it stays at the bottom peg.

Someone said I should replace the sending unit; I asked where it is located and I was told on the side of the head above the glow plugs. I've looked pictures of a new sender and it appears to be a 17mm brass fitting.

Problem is, I don't think I have located it on the engine yet. What I though was it--along with a very questionable wire coming out the top--may be correct but there appears to be *two* of these side by side. Located on the side of the head above the glow plugs, both have a single wire coming out of the top of them, both are brass, both appear to be 17mm.

Am I completely lost here? Anyone have pictures of a coolant temperature sender on the engine? TIA.