Fuse pops for brake lights soon as i put it in

My information shows, the 4th. fuse is 8A for Turn signals, Tail lights, Heated mirrors:
The 5th. is 16A for Brake lights, Shiftlock, ABS.
You should check carefully to see which fuse is blowing and what circuits it controls.
You are then able to trace those circuits to locate the short.

hot wire touching metal fuse blows so you don't burn up the wiring get it tested and fixed soon could be dangerous to keep putting in a new fuse

So, open the trunk of the car and see if you have a couple of plastic panels covering the taillights on each side, and an access panel to the extra brake light in the back window. That access may be either inside the car or from inside the trunk.
Remove the panels and remove the brake light bulbs. If you don't know which ones they are, take 'em all out, make yourself a map and tell yourself where each one came from, and set those aside.
Now replace that fuse again, and press the brake pedal. If the fuse blows, and you don't even have any brake light bulbs in, you have a short in the wiring somewhere.
This might be from an earlier car accident where some wire insulation has rubbed off, or from someone messing with the wires, like when someone adds a trailer wiring harness to the rear.
Let's pretend the fuse doesn't blow.
Now, put back one bulb at a time, and each time press the brake pedal to see if that was the offending bulb.
This should help you pinpoint the problem.

You might have a bad wirre in one of the tail light housings.they get corroded and rotten

you have a short somewhere in the brake wiring, you will need a multimeter and knowledge on how to use it to find the short, you can open the trunk, remove the interior pieces to gain access to the wiring to see if it is apparent to the eye where the damage is you might luck out

Check wire from fuse to light,there is short somewhere, also check light connector, has the car been in an accident lately?

you have a short check the wires if they have come together from the tail lights to the cabin

If the bulb is of too much wattage maybe but is more likely the wiring is grounding to the frame at some point. You are of course, using the proper fuse....

it is almost impossible to say exactly were you short is i would highly recommend taking this to the dealer they have the correct schematics and eletrical training to make this a fairly quick repair

chk. headlight switch, my guess thats what it is.