Technical One Radiator and Two Fans

[stevenk9958]

I have a 1978 Fiat 124 Spider 1800 and am getting ready to install the radiator. Much to my surprise, the buyer included a large yellow radiator cooling fan whose housing matches the bolt brackets and holes on the radiator which I haven't installed yet (see picture 1). When I turn the radiator over there is a smaller fan already installed on the radiator (see picture 2). Why two fans? Do I ignore the bigger yellow bladed fan and not install it and just use the smaller fan already installed? Do I use both? Thanks for any guidance you can provide.

 

[Slotman]

The yellow one is the original fan to the car...the other one is a small aftermarket fan, not sure why someone took off the original one unless it stopped working...