Header tank - water level sensor

[Cantata]

Hi all,
This is on a 2012 3.0TDi S-Line Avant.
Had a couple of 'false alarms' recently with the car telling me it's short of coolant, when it obviously wasn't. The first time it simply went away when I restarted the engine, the second time it persisted but went away after I waggled the wires on the sensor unit.
So it's maybe a loose or dirty connection there. I couldn't make out if the sensor has a plug/socket arrangement, or if it's hard-wired in. Does anyone happen to know? If it's a plug I couldn't see how to get it out.

 

[NHN]

Scratch the prongs on the reservoir with a flat screwdriver, see if it goes away.

 

[Cantata]

Scratch the prongs on the reservoir with a flat screwdriver, see if it goes away.

Thanks for responding. I guess you mean the prongs in the connector. Question is, how do you get the connector apart?

 

[B5NUT]

You need either lift the tank up slightly or remove the tank to get to the connector underneath.