To tighten a femals spade connector in a connector-block:

The connector has a tab which springs out of the bottom of the
connector when it is pushed into its block; this prevents the
connector from being pushed back out of the block when the male block
is plugged in. You can push this tab up with a thin screwdriver etc
and slide the connector out, then squeeze it gently with pliers to
tighten it. Then make sure the tab is projecting slightly and push the
connector back into the female block; it should lock into place.

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Regards
Andrew Grebneff
Dunedin, New Zealand
Fossil preparator
Mollusc, Toyota & VW van fanatic