BeeJay--two words for you: "
Continuity Tester".
Clip one lead on to one of the inputs, clip the tester's lead to another input. Listen for a "beeeeeep". (Or look for the light, whatever.) Press the button in, listen for "beeeep". Repeat. There are only 10 possible combinations (4+3+2+1)--it won't take as long as posting your query here...
Or you could use an ohmmeter--the light bulb will show a finite resistance, as opposed to just about zero or infinite for the rest.
--DD
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Pelican Parts 914 Tech Support
A few pics of my car:
http://www.pelicanparts.com/gallery/Dave_Darling