Right ok, iirc the fan switch should kick the fans in at 87-88 degrees, if you fit a new switch and the fans still don't come in and car continues to overheat its more than likely that your rad is blocked and restricting the flow of coolant,

to test when car is at running temp, feel the rad top n bottom, if top is red hot and bottom is cool its new rad time

and I don't know what switch that is but it aint a cossie one

Luciano