Heh. Turns out I'm not so good of a diagnostician. It was just a weak battery.

On other cars I've dealt with, a weak battery might produce a wimpy crank, or dim headlights, and when you crank the dim headlights would go out.

Not so with this C3. It either cranks strong, or doesn't crank at all. The headlights looked strong, and turning the key only dimmed them. So I thought the battery was ok.

But there was no click, the solenoid was not activating. And the ammeter showed a huge current draw, which I've been recently told means the starter is ok.

Aparently the solenoid needs a really solid amount of charge before it will activate. Is that a bad solenoid, or normal behavior?

I've got a battery tender on it now so it will keep the battery topped up.

 

You might want to get the battery tested as the problem you described could be caused by a bad ground connection or a battery going south. Most auto parts stores will test battery for free.