My 01 Explorer keeps blowing the fuse on the tail lights when you turn on the light. All other exterior lights work....

There isn’t a silver bullet type of fix for this kind of problem; it’s more of a search & rescue type of job. You just start looking for any signs of damage, corrosion; melted wiring that might be shorted to ground.
One of the first things, I look for when presented with one of these jobs is weather there’s a trailer wiring harness on the vehicle or any other after market lighting installed. If so, check them first by disconnecting them if easily done.
Next I would remove all of the exterior bulbs; one at a time, checking whether the fuse now holds. If so, that would be the starting point; working away from that bulb, looking for the shorted wire.
Then there’s a possibility that a sub system; like the cigarette lighter or power accessory port or the dome light that might be protected by the parking light fuse and one of them are the cause of the fuse blowing.
Metal objects like paper clips and coins like to fall into power ports or the lighter sockets. Even the plug-in that you may be using for a Cel phone or GPS could be at fault.

Dan.

Canadian "EH"

Went through each bulb and found passenager side parking light lamp assembly broken, replace with new one. I test drove the SUV and within 5 minutes the fuse blow again. I guess I will start the process over again. Hopefully I can find the short.

Dan has some real good suggestions to follow.

you didn't say if it had a trailer pigtail on it or not. If it has any kind of wiring harness tap into the rears, disconnect it. This is by no means scientific but I've noticed the longer it takes for the fuse to blow usually the farther away from the source the short is. I'd probably be looking in the rear for signs that Dan has already mentioned & also looking at a wiring diagram to see if there are any other circuits invovled...

I disconnect each external light and the fuse still blew, I started to connect one light at a time and the fuse blew each time. Now the fuse blows quick when I turn the light switch to parking lights. I also check the trailer light connector behind the drivers side tail light,. The connector has a dust cover, I check and clean the connector and replace the cover.

Best thing to do is disconnect that connector & recheck. Dan has a list of real good suggestion to follow some shorts are real tough to find and unfortunately there is only so much you can do online.

There are some more riskier things to try but the chance for doing some real damage is too great to try if you aren't intimately familiar with the process.........

If you want to save yourself some fuses; you can try using an old style glass sealed beam headlight, connected to the fuse panel; where the parking light fuse would normally be.
If you’re interested; make up a couple of jumper wires; (as long as you like) having female spade connectors at one end and male spade connectors at the other. Making sure that the connectors are of the proper size to connect to the headlight and plug into the fuse panel.
Remove the blown fuse and connect the jumper wires; one too each of the terminals where the fuse would normally be. Then connect the other ends of the jumpers to the terminals of the headlight; if it’s a three terminal headlight any two will work.
Once it’s all connected; turn on the parking light switch; the headlight will light and stay lit as long as the short to ground is there.
Now start disconnecting anything/everything that is attached to the parking light circuit; when the headlight goes out or very dim; you’ve found the short to ground.
You will not hurt anything in the circuit by doing this because the voltage drop across the headlight; is more or less and for the lack of better words, is using up all the voltage.
The only caution I have is; don’t lay the headlight on the seat or carpeting. The headlight will get hot (normal for any light) and could leave a burn mark.
Makes a good visual aid and you won’t have to be replacing the fuse, every time you want to try something.
Works good and you can place the headlight wherever you need to so you can see it from where you’re working.

Dan.

Canadian "EH"