radiator fan electrical?

[noob2soob22]

lright so i have an 83 gl wagon 1.8

my radiator was jerry rigged with a toggle switch on the hot wire of the radiator fan

 

i found that infact its the temp sensor on the side of the radiator that acts as the GROUND switch.

 

my first thought was that, the sensor was bad so they jumped it to be able to turn their fan on/off.

 

BUT, i found another temp sensor about 3" lower more towards the drain plug, with no wire connected?

 

im a little confused, which temp sensor should i be using.

 

also, is there a way to test the temp sensor?

Please please please. i dont want to lose my suby