where does the rubber pipe go?

hi, my son has removed the rubber hoses off of the egr system and dos'nt know where one goes back to, he thought one went on to the top of the auto box but that seems to pressurise the box forcing fluid out of the dipstick,we have one pipe going to a small module on the bulkhead which has an electrical connector but the other that has hot air going thru it and then we are at a loss, theres never another mondeo around when you want one, any ideas, thanx