I have an adjustable thermostat fan control unit with a probe that goes inside the radiator neck. It has a little rubber shim that the probe tube lays in, then the radiator hose goes over that. It works well, I no longer need it as I am having my engine computer control the fans now. I will sell it for $35 shipped if you are interested. I have the instructions for it as well. PM or email me at p.dilling@comcst.net if you would like a picture or more info.

You should also set up a relay for your fans so the full load of the fan does not have to go through the control/switch.

Pat