bjl97sen

ok new to the boards.. i drive a 97 sentra gxe..
question is.. under the hood.. the fuse box that is next to the battery on the left...
it has 2 rows.. of fuses... ( excuse the wording dont know much or what parts be called)... the row of little small fuses is fine.. but the row of the bigger square fuses is what its about... on the picture of the cover of the fuse box it tells u what fuse is what and where it goes.. but where the fuses go.. there is 1 missing.. and on the picture it shows its there... its the.. RAD FAN fuse..
on the pic.. it shows that there are 2.. one at the bottom.. and 1 2nd from the top (i believe).. and im wondering if its for the a/c.. cause my ac.. wont blow real cold like it used to.. i had someone check it and they said it was the compressor to be replaced.. but just wondering off this fuse.. what happends if i add one in it.. will it do something like boost up the fan or something or make it work like its supposed to.. (sorry for so long just new to here. thx)
any ideas. ?