How do I access a rear brake light bulb to replace it on a 1998 Ford explorer

Are the brake lights stuck on or are you just seeing the parking lights on without the brake lights lighting up? Sounds like you have no rear brake lights, check your emergency light switch. Sometimes it may not switch completely, turn it on and off a few time and then recheck it.

first thing is to check your brake light fuse, most cars trucks have a seperate fuse for the high mount brake light. If that is good check the bulbs, it wouldn't be the first time both bulbs blew at the same time.

another thing you have to check is the line(wiring) and if it is properly grounded..

Use this as a guide and a 12 volt test light, or multimeter to see if power at proper terminal from truck. If power there, then connection at trailer plug, or wiring from there to tail lights on trailer is faulty.

Open the back hatch and (if no screws on the outside of light cover) and look for a "door" or door panel that covers the inner side of the lights. Once this is off, find the brake light buld, twist and pull,or just pull out depending on bulb type. Put new bulb in, put door/cover back on, check brake light.

If there are not screws from the outside, the release happens inside. Often you have to remove interior trim for access, usually the entire light gets removed...

pop the trunk and right behind where the lights are pull the carpet down and their will be of the following depending on the trim.

You will either see the light sockets themselves that you can twist and pull to change the bulb, or you will see the plastic nuts/screws that you can remove to remove the entire assembly in order to access the bulbs.

If it's your 3rd brake light, the screws to access the housing are located in the upper part of the trunk

the bulb may be shorted to the other element in the bulb,,replace that bulb and it should go away

this is not a bulb u must replace the entire LED fixture, to do this remove the inside trim at rear around rear hatch opening, then you will need to drop the headliner down to access the retainers that hold the third brake fixture in, very easy job.

Check and make sure you have the right bulbs and fuses installed. However, it sounds like a wiring problem. Probably at the rear of the vehicle. If you are in a "snow" area state, the ice and snow formation can break or pull wires apart. Also, check your ground wires.