2000 I30 Stop Light Switch

That's the one. The first thing to check is whether it is securely mounted and adjusted properly. Check that the button moves freely when the pedal is pressed. Then verify that the electrical connector on it is also clean and securely attached. If it still doesn't work reliably at that point then replace it. It should be easy to replace.

sounds like a good place to start your diagnosis.

After numerous tests, it looks like it is the stop lamp switch - sometimes it works and sometimes it doesn't. I got the part from the dealer today but can't figure out how to install it. First of all, the dealer warned me that the first and easiest to get to switch is the cruise control one - it looks exactly the same as the stop light switch but with a brown end. After some looking around I finally found the stop light switch - it's right next to the cruise control one. It's really hard to get to from underneath the dashboard - the steering column (at least that what I think it is) is in the way and I can hardly even see the switch. It seems to be attached to some kind of metal bracket with a plastic nut but I couldn't unscrew it with my hand. Is that really a nut? Should I force it with pliers? Anyone has an installation diagram?