found a new fan for a Sonota - it does not list the amps , but has wiring harness that offers 2 speeds ( I will try the lower speed first to see how it cools ) I needed to trim the sides off but it fits perfect over the single core radiator - gives 1 “ clearance from water pump . I was able to secure it tight with 5 zip ties ( I will add some L brackets soon ) my question is : I want the fan to come on when car is turned on . I bought a 100a relay switch that is pretty straight forward , but I am unclear on a few things . the fan has 2 wires , does the fan get grounded to the car body ? If so , why does the rely need to be grounded ? Also , the “positive trigger” on the relay is simple the ignition wire ( like a car radio or amplifier ?