Here's a link to what you're looking for . Make sure you ask for underwater lights as the regular trailer lights wont last very long . I learned the hard way trying to save a few bucks . Most auto parts places or west marine carry them . Or go to G&H . Dont pull all the old wires as you will use them to pull the new ones in . If you run into trouble feel free to PM me I may be able to help you out.
http://www.amazon.com/LED-Low-Profil.../dp/B000CHMG26