I istalled the thermostat from my new flex-a-lite e-fan in the radiator fins in the upper edge above the fan shrould (you can see that on the pic).
But it doesn´t work very good in this position. When I stand at a traffic light the fan turns on at about 210 degrees. When I drive slow in the city the temperature goes up to 220 degrees and the fan doesn´t turn on.
I´ve the feeling that the thermostat turns the fan on because of the heat under the hood and not because of the heat of the radiator.
My probelem is that the A/C radiator is in front of the noirmal radiator. I can´t stick the thermostat through the fins on anoher place.
Where did you install the thermostat on your TJ? Got Pics?