Radiator fan 72 350

I've got a 72 hot rodded corvette (no where near original).

The radiator has an electric fan on it. Currently it is wired to the ignition so that it comes on when the car is started. It keeps blowing the fuse so I would like to wire this properly but I don't think an electric fan was standard for 72. Mechanic has told me there should be a temperature sensor on the front passenger side of the block that controls when the fan comes on but I can not find such a part. There is a temperature sensor on the lower drivers side that hooks in with the headlight wiring assembly but it controls the temperature gauge (which is accurate).

I would like for the fan to kick on when the temperature crosses a certain threshold without having it hot wired to the ignition....or advice on how to keep fuse from blowing because of this.

Thanks.  

you really might want to take a look at this product through speedway

http://www.speedwaymotors.com/Electronic-Cooling-Fan-Control,2356.html?parentDisplayId=2350

many manufacturers also make similar but mechanical versions...like this one

http://www.speedwaymotors.com/Adjustable-Electric-Fan-Control-Kit,2350.html

there was also on model of car.. that had a thermal sensor on the electric cooling fan mounting leg...     when the thermostat opened..  the hot coolant in the radiator caused the thermal switch to close causing the relay to turn the fan on...   when the coolant in the radiator temp dropped...  the sensor opened.. shutting off the relay..

some cars also had a time delay relay...  to control the cooling fan... this helped with the heat soak after shut down...  ran the fan when you shut off the key to take excess heat out from under the hood...

some toyotas came with a power steering fluid powered hydraulic fan... it also had a thermostatic control...  and reduced the amount of power needed to be produced by the alternator for the rest of the car...

if you like any of these other ideas...    do ask...  but the first link will work great...  

Thank you, first link is great.