actually it is the Thermoswitch, the coolant temp sensor or water temp sensor is used to read the temperature of the water for your gauge/etc...h:

The thermoswitch is located here.

 

is the switch the one that is screwed in to the motor.or is it the blue looking thing.if i unscrew it will any fluid come out.

 

it is the thingy with the clip attached to it....it is a 17mm if I remember correctly, and yes fluid will come out when you change it.

 

what type of motor is the above picture.i have a b16 and it looks a lil diff.i removed a clip that looks like and and unscrewed it.i used a 19mm.and coolant came out.is there maybe another one that looks like it.

 

That something i haven't seen i got the old Dinosaur car the EF 88" Hatchback Talk about Roming the Earth!!!!! LOL

 

that is also a b16a......and yes I beleive it is 19mm not 17mm I couldnt remember which one it was. Yours wont be blue...that one is blue because it is a Spoon Sports thermoswitch.

 

i change the thermoswitch today and my fan still does not go on.my car started over heating again.i bought a new relay for the cooling fan and it still does not go on.i checked if my fan works and it does.now im back at nothing what else can it be.i really need some help here.

 

get out your trusty DVOM and test the wires from the thermoswitch to the fan.

 

is there also another sensor.do they sell a thermoswitch.

 

what do you mean do they sell them....I thought you said you changed it