1997 Oldsmobile Cutlass radiator fan

turn A/C to full blast. fan should come on. if not, supply 12v power directly to fan motor. if fan comes on then check fuses and relays. if doesnt come on replace it.

and if the a/c hasn't worked in two summers?? this tests fan but what about the sensors just cause fan works with 12 volts doesn't mean it works WHEN it should

you asked easiest way to test the fan, not the sensors... if you're wanting to test the engine coolant temp.
https://www.2carpros.com/topics/climate-control/air-conditioner