A light coating of silicone lubricant, available as a spray, on the bulb threads, will lubricate the bulb and socket, and be electrically safe, and will make future removal much easier. Only a LIGHT coating, or short spurt of silicone, wiped over the bulb base, should be used.
Facing the rear license plate of the car, place your hand in the upper portion in front of the license plate and you'll feel the rubber light socket which you would turn clockwise to remove. If the socket is too tight to turn and remove, then with a Phillips head screw driver remove the two screws that hold the plastic lens and socket which should drop down and make it easier to manipulate. The rubber socket has a remove direction arrow imprinted on it. Reverse procedure to re-install.
If you want to you could remove the light socket and put in an outlet then plug your light into the outlet.
If it's like my 88 remove license plate, remove wire to backup light, pull backup light assembly straight out (sideways), reach hand to taillight socket, twist socket and remove.
Remove the screw from the lamp(under the hood). disengage the assembly (it has snaps on the bottom) by pulling straight out. Turn bulb socket 1/4 turn to remove.
It is hot and you can turn on and off a light bulb by screwing clockwise or counterclockwise.
once you remove the bottom tray, the fog light has three screws, all three a pointed directly down and a socket will fit with no clearance problems. Take the two top screws that hold on the foglight bracket off and the bottom center screw.
Remove brake light interior trim panels. Then you push and twist the socket for the brake light that needs replacing. Then pull out socket. then pull out bulb from socket and place new bulb in the light socket. Once bulb is installed into light socket. Place the socket where you removed it from brake light housing. Push and twist clockwise to lock back in place. Then replace trim panels.
If you have 120 v at the wires connecting to the light fixture the light should come on. Its possible the voltage is not getting to the inside of the socket. Carefully measure the voltage between the metal blip at the bottom of the socket and the metal along the sides. Be careful here. Its tight quarters and easy for the voltmeter leads to touch the wrong things. Before doing that I would try a third light bulb. I've gotten them bad right out of the package. If you have voltage inside the socket, then for some reason the light bulb is not screwing far enough down so the bottom touches that metal blip on the bottom of the socket. If you don't have voltage inside the socket then that's your problem and you'll need a new socket.
Open the trunk and remove the nuts holding the assembly in place. With nuts removed the tail light assembly will come out the back then you can remove the light socket to replace the bulb.
The bulb socket twists out counter clockwise 1/4 a turn. Then remove the socket from the housing. Remove the bulb from the socket and replace with a new one. installations is reverse.
THRU THE TRUNKThe tail lights are replaced through the trunk. The license plate light is replaced by eitherundoing the two screws that flank the light,pulling the fixture down,removing the bulb socket,replace the bulb and reverse to reassembleORreach up from under the bumper to remove the bulb socket,replace the bulb and return the socket.If you don't know where the socket is, or don't have a flexible wrist, it's easier to undo the screws
Dead short to ground in either: Parking light socket or wire to Tail light socket or wire to Dash panel lights Remove 1 bulb and/or socket at a time to try to determine which is bad