frequent breaks problems

[Chris.k]

Hello guys.

I need your help. I have Insignia 1.6t petrol age 2009. My car when im going to highway with normal speed makes small frequent breaks .... this happen if im using A/C  And if i use cruise contol and happend that small breaks the car stop the cruise control...

The computer diagnosis cant find any problem 

Any idea ?

Thanks

[Vauxhall Owners Club]

It may be a faulty brake light switch causing the issue