Everything OK...unfortunately with winter tires

Previously, all oils were changed, including ATF.
Now to my question I have already read one or the other about the cruise control! Giver signal with me OK! Relays clack .. not with me

I noticed the switch at the brake pedal, with me a hose goes away and goes towards the spray wall.
Can the hose have anything to do with pressure/low pressure??
Greetings Harald