Xantia coolant level sensor test

[XUD9]

Good evening! Does any of you know how to check my coolant level sensor (OEM: 9623733580) ? It should be resistance, right?
Citroen Xantia 1.9TD 1995

Last week I overheated the engine thanks to coolant leak. I was not aware until the temperature reached 105°C... Luckily there are no damages to the engine, but I want to prevent similar situations in the future.

I'm not sure what it should trigger as warning light too. Once I know the way it operates, a test will be performed.
Thanks in advance!

[xantia_v6]

The sensor detects the coolant level, probably bye resistance. There are electronics in it to directly drive the warning light. It requires a 12V supply to operate, and the output switches to ground.

[Stickyfinger]

Take it out of water, it should light the bulb....if not check the 12v feed, earth and the bulb in the dash.

It does NOT detect temperature......