[6pack] radiator fan switch

[Pim Alferink]

I run such a setup as well. Regular thermostat switch with bulbsensor.
Bulbsensor taped to the radiator return line (to the metal pipe). Works
perfect and one can set the temperature at which the fan comes in using the
dial on the thermostat. Accurate within a gedree or so.
As others advised, I included a switch for manual on/off. But after five
years I still never used it. Oh and two years ago I did away with the
mechanical fan.
Pim 73 Pimento

Earlier today I saw a TR6 with an electrical fan, with the thermostat
located in the metal pipe between the 2 hoses that go from the water pump to
the bottom of the radiator. if you can find the source for that pipe and
thermostat, that would give you another option over a manual only on-off
switch.