There are several relays under the hood, and I would suspect that you are right - one of more of them may be stuck in the ON position.
Here is a diagram of their location. I would start by "feeling" them to see if one is hot, and then remove that one first to see if the fan goes off. Then continue removing relays - one at a time - to see which one it might be. That should get you to the correct relay in the shortest period of time.
Please let me know what you find.
Take Care, Greg A.
That sound very reasonable. Drawing a lot of current for a long period of time can get things hot! I think you are on the right track.
Try to be careful getting them loose. Melted plastic has a way of getting in the open areas. It may be necessary to "chip away" some of the burned plastic to get these out. Just take your time and try NOT to damage the sockets that the relays plug into.