What do the relays and fuses look like under the hook of a 96 s 10 blazer. Someone said to check theses and how do you. My brake lights dont work and the 10A fuse under the dash is good and i replaced the break petal switch but still no break lights.

Did you check or replace the brake light bulbs?
It is more common to have burnt bulbs than a bad brake light switch or blown fuse.
Do you have orange signal lights and red brake lights at the rear?
Then the signal light switch will not affect the brake lights.....but....
If they are all red and you use the same bulbs for brake and signal....the brake light wiring goes through the signal light switch and could be affected there.
First....check for power getting to the brake light switch......and leaving it with a test light.......then go to the rear....pull a light assembly and check for power getting to the bulbs.no power? follow the wiring back to the switch looking for a bad connection.
The fuses and relays under the hood are usually in a black plastic box labeled fuses and or relays.