i thought 3-2 programs were along the lines of:
spend 3 years doing a B.A. at a liberal arts college in some field (could be physics... could be art history). at the same time, you do all the lower division courses for engr school (gen chem, calc, physics, etc)
after those 3 years, you enroll at an engr college for an engr degree (Columbia has a large program with its Flu school of engr) and spend 2 years doing your upper div engr classes like any other engr major.
at the end of 5 years, you get both degrees. these programs typically work on the arrangement between the engr school and the liberal arts school.