Fan/wiper fuse blown

[Steve Sherman]

Had to recue my wife and her 87 5KTQW just a bit ago.  [I know this is a
20v forum, but the audifans site does not allow one to belong to
multiple lists, and the cooling system here is fairly similar between
the 5K and the 20v's]

 Car had overheated while going up a steep hill, and she stopped and
pulled over when she saw steam coming out of under the hood. When I got
there and looked into things, the only problem (other than AF having
shot out of the res) was the fan control/wiper fuse had blown.  The wife
mentioned that the wipers quit on her about 10min or so before the
overheat event (but she was driving on the level until this last hill).
So from what I could piece together, this fuse blew, so no cooling fan
and things overheated.

I replaced the fuse and refilled the AF and drove home.  Basically
everything was fine.  Fuse is doing fine, fan works (only 1.5yr old, no
binding), wipers work.

So I am curious if any listers have seen similar symptoms before.  Any
ideas what might cause the fan/wiper fuse to blow and then go away?

TIA