Coolant level sensor wiring ?s

[desertspeed]

I just got a new buggy and am in the process of re-wiring. It is water cooled (a 2.0L VW Jetta motor) and the coolant tank has a sensor in it that is wired to an idiot light, but it does not work. The sensor has 2 connectors- 1 is wired to ground and the other to the idiot light in the dash. The other connector of the idiot light is wired to the IGN power. I pulled out the sensor and the 2 connectors are attached to metal probes that stick down into the tank- see photo.
The two connectors/probes are separate, and if they are connected the circuit is closed and the light will go on. However, I can't figure out how to make the circuit connect when the coolant level is low as it is supposed to- I can't quite figure out how the sensor could ground when the fluid level is low- any ideas?

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[powerbox_builder]

That sensor in the picture looks pretty shabby. Looks like one electrode is rotted away. If it was already hooked up and he says it used to work, then I would try replacing the sensor. Anyway that sensor measures the resistance created when it's submerged in coolant. VW uses a microprocessor in the instrument cluster to turn that signal (or lack of) into a flashing light. Unfortunately this means the only way you can get it to work is if you have a friend that is an electrical engineer and can build you a circuit, or mabey you can canibalize the Jetta instrument cluster and somehow make it work. Good luck.

[ntsqd]

What is the purpose of the sensor and the light? Is it worth worrying about? So far it wouldn't matter to me.

[200MPHTape]

You said it yourself, its and ID ten T light! (IDIOT) I'am no expert but it is part of the systems check, the coolant level is low the light comes on. And we all know(I hope) that you dont wait for the light to check your fluid levels!

[powerbox_builder]

It is your first indication that you sprung a leak. Would you rather get a light when you are a pint low, or happen to glance down at the gauge and find it in the red? Or better yet wait for the smell or the loss of power.

[desertspeed]

I am not sure that it ever worked- it is not essential that I have it working but the sensor is there and the wiring is there and I have a spare light on my dash, so I figured if it was easy I would use it. As previously mentioned, it is better than finding out you have a leak after the smoking starts. Looks like there is no easy way to make it work...