New HU/now brake and cruise gone

ok guys. I got a dvd HU installed, and a few days later my cruise and brake lights work when they wanna work. is there any way it could be related? i know the brake switches are known for failing so i pulled it apart and it looked good. then i pulled and put back the relay in the fuse box and it seemed to fix it. oh and i have a 2011 crew cab with 30k. would have installed it myself but had never messed with the onstar crap so i got best buy to do it. thanks.