Hi All
I've Mercedes E220 model 1993. I've a problem with my Auxillary fan. The fuse of the Auxillary fan keeps burning. I went to mechanic to replace the auxillay fan, but no use. The fuse kept burning (I replaced it with a second hand fan).

So, I would appreciate if you can provide me with the reasons that causes this to happen (all possible reasons).
Note: The mechanic says that the fan gets hot after spinning for a while, that's why he judged that I need to replace the fan.