sensor hose

i just replaced my radiator and i unhooked a hose and forgot where it hooks up to i know that it came off the little sensor looking thing next to the oil and air seperator. the hose says CAN and has an arrow.(i assume that is telling me which end goes to the CAN) but i dont know where the other end hooks up, or what the CAN is. there are two hoses on the sensor i need to know where the bottom hose goes. this pic shows where the hose hooks up
here is a pic of where it hooks up
http://gallery.cybertarp.com/displayimage.php?pos=-250605