Originally Posted by martysmartie

Yes it will do what you want, i.e. an OVERRIDE switch, so the fans will cycle via the switch as normal.

You can use a piggyback connection, by this do you mean a 'Scotchlock'?

It's just to run another connection from the wire from the relay side which goes to the fan switch.

That is all thats needed, you don't need any other components.

Martin