Unisolated wires under Coolant expansion tank; What have they been used for ?

[thyrsted@olsy.dk (Kenn Thyrsted Nielsen)]

Hi, all.

I removed my Coolant expansion tank today, on my 200 TQA, and found two
wires under it.
They are (were) unisolated at the ends and of normal size.
Obviously the former owner have removed something from down there.
The big question is : What was it ??
the colours are brown and blue/yellow (or yellow/blue).
The latter has 12V on it when i turn ignition on.

Could it have been for a coolant level warning sensor ??

TIA

Kenn; '87 200TQA