I want to install a digital water temp gauge I don't know where to install the sensor. I was told there is 3 sensor on my motor and that one I don't need but I don't know wich one it is. If anyone could help me out pictures would help alot too

 

Any help?

 

When I did a water temp guage I used an adapter in the upper radiator hose where I could mount the sender. I kept all the stock sensors in place.