Hi. I hope you guys can help me

Last week I bought a 2006 V70.
Cruise control worked to begin with, but now it doesn't.
The cruise control buttons don't illuminate and "never" did (volume buttons etc. do)
No error messages in the instrument panel.
I've done the clutch position sensor test (clutch down, neutral).
Brake lights work when I depress the brake pedal.
I've had the airbag off and checked the connectors.
The brake booster vacuum sensor makes a long buzzing noise on startup and every 5 seconds with ignition in position II and when I depress the brake pedal ... (?) I've taken this off, and it hasn't changed anything ...

I don't have a fault code reader, is there anything else I can check before taking it to a mechanic?

Thank you so much