electric fan sensor location

Depending on the manifold, you could drill and tap it. I have 3 sending units as well as one for my gauge. I drilled and tapped for the additional 2. I attached a pic, it is hard to see but you can see the 4 temp units. I am using a electric water pump so I used the bypass outlet for my gauge. The other 3 are water pump,fan and ecu. Hope this helps