2002 Sentra SE-R Gauge Problem

I have two problems, and I was wondering if it will cost more than it's worth to fix, or could I fix it myself, I'm not good at any electrical work. And is this a common thing to fail. My temp. gauge needle jumps around, If it goes all the way up I can bang on the dash and it comes back to normal, or hitting bumps in the road will make it move around. It never stays in one place for too long. My car is not overheating at all. Could something be shorting out? Second, my parking break light is now doing the same thing coming on and going off. Everything else is ok. My car is an automatic, I don't use the parking break, but I tried it to see if it works and it does release the break ok. So does this sound like some kind of short, or what do you think? Thank You in advance for any help. Ed