Suddenly a warning light blinked.

突然有一盏警告灯开始闪烁。

《牛津词典》

The plane was flying normally for about 15 minutes before a warning light blinked on.

飞机正常飞行15分钟后警示灯开始闪烁。

《柯林斯英汉双解大词典》

Suddenly, a red warning light turned on.

突然，一个红色警告灯亮了。

youdao

All down: When farm commodities are uniformly depressed, that's a warning light flashing.

FORBES: Fact and Comment

The red Fire Warning light is bad news when it lights up, but you can silence the alarm bell by pressing it.

FORBES: What Do All The Controls In An Airplane Cockpit Do?

And under International Civil Aviation Organisation regulations, any structure over 45 metres tall on a flight path or near an aerodrome must be fitted with a medium-intensity aircraft warning light.

BBC: London helicopter crash: What are the rules for pilots?