Power lock problem

I recently purchased a ’92 econoline. I’ve now noticed that there is a problem with the power locks, as they will sometimes unlock themselves. The other day, I went out to the van and the doors were unlocked. I knew that I had locked them, so I locked them again and a couple seconds later, they unlocked by themselves. The power lock buttons and the key fob also sometimes don’t work at all (I’m guessing that may be a short?).

Is this a problem with the remote unlock? I was thinking about just pulling the fuse for the power locks, but I don’t know which one it is, or if it controls more that just the locks. The fuses aren’t labeled and I don’t have an owner’s manual.

Any help or advice would be appreciated!