light dawned

light dawns (on one)

To understand or realize something with sudden clarity or certainty. The light finally dawned when I remembered that my grandfather had been stationed in Japan many years ago. She'd been cheating on me for months, but it was only when he left his tie in the house that the light dawned on me.
See also: dawn, light

(the) light ˈdawned (on somebody)

somebody suddenly understood or began to understand something: I puzzled over the problem for ages before the light suddenly dawned on me.
See also: dawn, light