How do u take tail light off to replace brakelight 2001 grand prix

Go back and check for a bent pin or a wire backed out.

It is usually the taillight fuse .If your tail lights work, turn the dimmer wheel up for interior lights

My first guess would be a ground problem.
The headlights and tail lights are controlled by the same headlight switch, but the brake lights are on a totally different circuit.
You may have to get a shop manual to get the wiring diagrams needed to troubleshoot the circuits if the ground connections are ok.
The lights involve the body computer and other components.

no, they are not the same. The multifunction switch is on the steering column and controls wipers, turn signals, and hi/low beam headlights. Dash switch is on the dash and generally turns lights on and off and frequently also controls brightness of dash lights. I had a Camry that had the same thing happening...ended up having a toggle switch put in to control the tail lights...fixed the issue.

open trunk and remove the cardbord/carpet cover right behind the tail light and you will see 3 plastic wing nuts remove the nuts and then remove the tail light assy. then it will be self explanatory how to change the bulbs.....GOOD LUCK

fuse to check should be brake -running -ligths but i think they run off the same fuse . or look for tail lps fuse in panel

Owners manuel chapter 11 & 12 should show you the fuse box placement and layout..there are two fuse boxes, inside behind the coin holder to the left of the steering wheel, slide out the holder..I believe #5 on the fuse box is the fuse for tail/brake lights. Also under the hood in the engine compartment on drivers side there is the main fuse box.

IT'S A BIT MORE COMPLICATED THAN ABOVE.
TO REMOVE BRAKE LIGHT HOUSING YOU HAVE TO GO INTO THE TRUNK AND REMOVE AN OVAL PLASTIC COVER NEAR WHERE THE TAIL LIGHT IS. REACH IN AND FEEL FOR A KNOB (FEELS LIKE AN OUTDOOR SPIGOT KNOB). TURN IT UNTIL IT COMES OFF. REMOVE ENTIRE TAIL LIGHT CASING. YOU'LL BE ABLE TO COMPLETELY REMOVE THE HOUSING BY PUSHING FROM INSIDE OUT. DISCONNECT THE WIRE. CHANGE BULB, REVERSE PROCEDURE.
GOOD LUCK.

Check to make sure you have the correct bulb in them. Even though the parts store may have had a part number, sometimes they don't get them right. If those are correct check the relays and or the socket itself.