I did a little searching around, using the search option in the tool bar. Looks as though there are not a lot of Melex carts out there, compared to CC and EZGO at any rate. I did see a post that mentioned something about Melex and EZGO being very similar, but I can't verify that.
I did look at this website,
https://www.vintagegolfcartparts.com.../melex_manuals , they have manuals and wiring diagrams available for sale.
Hope this helps...