The aux fan on the subject model vehicle has nothing whatsoever to do with the engine. It is actuated by a temp switch on the a/c receiver/drier and nothing else. It will only come on if the refrigerant temp gets hot enough (62 degrees C) to close the switch. (If you refrigerant level is a bit low, it might never get hot enough, even with the a/c operating.)

With the key in "Run," jumpering the temp switch on the receiver/drier should actuate the fan relay and power the fan. The relay is powered through fuse 12; the fan through fuse C.