my understanding is that water comes out the bottom rad hose on the drivers side of the car and into the engine under the turbo where it stays(in the engine) until it reaches 88 deg then the thermostat opens letting the hot water out and into the top of the rad on the right hand side.

the fans only run when the fan switch senses that the water temp in the rad is above a certain level.

the fans and thermostat are not linked in any way and operate independantly.

so best place to fit the water temp sensor would be in the hose going in to the engine under turbo??