Years ago I had a coolant light with a life of its own. On probably the
third time that I had the instrument cluster out trying to get rid of the
gremlin, I detected looseness of the flexible circuit paper connection. I
took a small thin piece of  cardboard, like cereal box thickness or less,
inserted it where the circuit paper wraps around before it is inserted for
the connection to wiring; this fattens the inserted piece a little to make a
better connection. Making sure you did not fatten the insertion area of the
flexible circuit paper too much, put it back together. Since it's been
years, I may be a bit hazy on detail of the connection, but I hope you get
the concept. It cured my coolant light problem, and haven't had to take the
connection apart since then.

Ron Ourada 85 wtrbxr