Three-year-long story short: No turn signal indication on the dash,
other than the relay clicking. Over this winter, on cold days, temp
needle went nuts and temp LED flashed until car was warmed up.

Replace the temp "relay" and the temp needle calmed down for good, it
always operates properly now--which is strange, because I wam told
that the relay controls the light, not the needle.

At first the blinking light would not quit and as the car warmed up,
this blinking because so intense that for all practical purposes the
light was always on at normal temps.

Then this quit, and my turn signal indicator light started working for
no apparent reason as long as the headlights were off. If they were
on, no turn signal indicator light.

Sooooo, I thought to myself, "very good, better anyway, but you
haven't done anything to improve the grounds.

So I did as Mark D. and other suggested and cut the two brown wires to
the big connector and soldered them to a big common ground wire with a
ring, and put that under the big screw supporting the heater lever
assembly. I soldered the two "tail" ends together.

Now I get this: no turn signal indication under any circumstances, and
the temp LED blinks unless I cycle the key on and off a few times to
kill it.

Jim