Is the part below the Temp Gauge Sensor? If so, is there a way to plug that some place else? The radiator I'm getting do not have the hole to screw this in (Civic radiator). On the Majestic website, it says it's a "switch assembly - thermo - Nippon thermostat".

 

No, that is the fan switch. The temp sensor is in the coolant passage on the intake manifold.

 

Okay now that's gonna suck. This means I cannot re-use my OEM radiator fan when changing radiator? Is there another way to turn on the fan?

 

If you could find out what the thread pitch/size is on the fan switch you might be able to find something like this:
http://www.jegs.com/p/Flex-a-lite/Fl...17700/10002/-1
This can be ran inline with the lower radiator hose and will just require extending the factory wires.

Maybe you can contact these guys and see if they can make one specific for the fan switch.
http://www.ebay.com/itm/40mm-1-57-Wa...sories&vxp=mtr

 

Good stuff DC. Thanks!

I was also thinking of getting a universal radiator fan switch.

http://www.ebay.com/itm/Hayden-Fan-S...5c7dc0&vxp=mtr