what is that lump on the top of my dashboard ?

[Poltroon]

I have a nice new Octavia which I'm loving.

On the top surface of the dash there is a heating/cooling vent that runs the full width of the windscreen. Right in the middle is a small black "thing" about 40mm square with a curved lump sticking upward in its centre. Okay ... so what does it do (apart from making annoying reflections in the glass that is) ?

[Pana]

sensor for the climate control.

[K1W1]

What he said.