The Ford manuals are also available in digital form through Bishko
. That's where I got the Service Manual and EVTM for my '95, which shows an almost identical diagram for that circuit. Almost.
The fuse number is different on my '95, as are the lamp pin number and ground point numbers- minor differences which I would expect to change between generations. But the troubleshooting procedures are written up a little differently, and the chart in post #6 mentions a "float" that doesn't sound consistent with the 2-prong sensor you have. Your 2-prong sensor sounds much more like like the one on my '95, which looks identical to LMR's "1990-95" compatible sensor, neither of which use a float.
I'd feel better if we could make sure that we're looking at the correct info here. The photos in post #6 certainly appear to be from an official Ford manual, but it would be nice to confirm the year and model.
Who knows, maybe the whole "float" thing is just a typo. But there's another thing that sticks out to me here- a note in my 1995 diagram pointing to the low engine coolant switch that says:
When closed, supplies ground to turn on the coolant indicator lamp for several seconds, when the ignition switch is turned to start or run continuously when the coolant level drops 2 inches below the full cold mark on the side of the recovery bottle.
This function detail is absent from the manual pics shown in post #6. Was the brief initial illumination (bulb test) feature an updated design for SN95 cars? Could it be that the Foxbodies did in fact use a float-type sensor which could be tested via simple continuity check, and that the slightly more complex two-prong piece with its little potted module is a backwards-compatible replacement?
Anyway, getting back on track here, it sounds like your sensor was probably shorted. Looking forward to hearing if the new one fixes the problem...