Nothing more frustrating than electrical problems.....

Look at all the grounds for the circuit items involved, including the tail lights. If there is a faulty ground the current will find the next lowest resistance path. I wish I could tell you the locations for the grounds, but I just don't know.

Have you checked for shorts in the doors? Maybe open all the doors to change the stress on and position of the wires to see what happens.

Your problem could be caused by some seemingly unrelated electrical circuit. Try isolating the electrical circuits and bring them on one by one and see which one causes this fuse to blow.

Does everything else seem to work properly when this fuse is out?

Keep trying.

Dan