Front marker lights can be changed by removing front headlight assembly. To remove pull up on two metal clips behind light assembly and unplug wires. The side marker lights are now accessable. Turn bulb socket ccw to remove.
open trunk, remove the 4 wing nuts, remove the casing from the outside. Bulbs are in there.
burnt bulbs, switch or fuse.
IT not to hard to change .take the Phillips screw out on the side of the marker lamp then open the hood and open the plastic black door behind headlamp. you will need a 11 millermeter wrench or socket .take the bolt off the back of the marker lite and it will come right out.
Check the bulbs, the fuse then the brake light switch.
3. 2 for the main lites, and 1 in the center
Changing out side marker bulbs are easy. All you have to do is unscrew the old one and screw in the new one.
You probably have a bulb out. Remember, the rear has two blinker bulbs
you have to remove the cover of the dashboard to replace the light bulbs
From inside the trunk, remove the wing nuts and just pull the whole assembly to the out side. Bulbs are in there.
You have to remove front headlight piece (which is held by two screws). Once removed you will be able to see and reach the bulb connection on the back of the side marker.
There is a short in the wiring or in the bulb. Try changing the bulbs first.
Open the trunk take the plastic srew behind taillight out and move the pice of trunk rug out of the way. You should be able to see the back of the bulbs just turn them to left and they will come right out. (you did not say what year)