You're going to have to crawl under those steps and look. Monaco used a little Radio Shack window sensor magnet to show open/close. The magnet comes loose and then the light stays on. You will have to find the correct closed position and realign the two pieces. Clean the surfaces very well with acetone, then use 3M molding tape...the black super stick stuff and your light will work once again.
Be careful that door is completely opened/closed and switch is off when working under there...it would be a heck of a pinch point. :( :(
http://www.amazon.com/Window-Contact.../dp/B0056K5ZC2
This is what you are looking for only the wires are probably inside black wire loom.