Crazy water temp gauge.

[Ben Fenner]

A few weeks ago my stock water temp gauge started failing under high load,
WOT, above 4,800 RPM, or a combination of the three. It reads normal (in the
middle) and as soon as I but some stress on the engine in the higher RPM
range the guage begins to flutter and peg towards the bottom in the most
extreme cases. Once I back off the throttle, the guage imediately returns to
normal. A few days after this started, my starter stopped working. After
replacing every possative connection (moved battery to trunk) and a new
starter, I realized the ground from the engine to the chassis was worn down
and corroded. After replacing the stock 4 gauge ground with a 2 gauge, and a
4 guage, my starter would start, and the temp guage returned to normal. The
temp gauge is back to it's old tricks now though, and I've ruled out poor
grounding as the cause. I have the FSM, but can't find the location of the
sending unit for the life of me. Where are the electrical connections I am
looking for? Or is this a sign of something else, maybe non-electrical? And
why does this happen only under load? This is puzzling.

-Ben
1994 Black SE-R