Hi, I have a 1990 Hyundai Sonata, and over the past few weeks, I have had
intermittent problems starting the car.

The accessory lights and everything else (headlights, etc) would work fine,
but no cranking of the engine, just a click followed by a kind of whining
sound from the engine bay (an electrical whining though, not a mechanical
whine).

I could always overcome this problem by popping the bonnet (hood) and
twisting the negative terminal connector of the battery and making sure it
was on properly.

This worked every time, but now even that has stopped working, and no matter
how nice and clean and tight I make the connection of the terminal, still
the car won't start. No cranking, just that click and whine. Headlights
still work, interior lights work.... everything but the actual starting of
the car.

Any ideas what's up? Any info would be great

Cheers,
Martin