Driving me crazy

My wife’s car is driving me crazy!  The brake lights are intermittently not working.  Sometimes they are fine, sometimes they don’t work.  I’ve taken the car to the shop three times now and asked them to fix it, and they keep telling me that they are working fine when they check it.  They even gave me an inspection sticker for the car!  I think that they were just being lazy and didn’t want to troubleshoot the wiring.  I really can’t blame them for not wanting to do that, it will be a pain in the neck to do it.  But I guess I’m going to have to break down and do it myself, it needs to be done!