Joel Walker scores a couple of points with his suggestion that I should
"wiggle the hell out of that dash multiconnector".
I didn't actually do that, but I took it apart and cleaned the contact
surfaces on the floppy plastic circuit-foil, even the ones under nuts and
washers that I suppose connect to the actual gauges and lights.
This was a couple of days ago, and it has worked fine since. A bonus was
that the temperature gauge now goes up to the accustomed position on the
right edge of the red lens for the light. That hasn't been the case since
early summer.
I will replace the sensor and gasket anyway, because I've already ordered them.

Thank you, listees.

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    '62 Johan Nyberg, Sodertalje Sweden
    '86 Caravelle C    Necessary Pest
    '62 Kerstin        Wife
    '85 Aasa           Daughter
    '87 David          Son
    '88 Markus         Son
    '91 Jonas          Son
    '93 Tora           Daughter

    (Signature concept gratefully stolen from Tim Casey)
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