I just purchased a working NAV unit out of an M5 from eBay for $400. Of course, I found this thread afterwards!

Upon swapping out the monitors, I saw my 2001 530i had monitor part number:

LQ065T9BR53..........2808935 D

Now I know in the past that my NAV unit had been replaced once due to dead pixels under warranty.

The unit from eBay was LQ065T9BR52U. It seems to work just fine in my 2001 530i although the screen is scratched a bit more than I would like, at least all the pixels work.

I'm thinking to purchase two new monitors, replace my 'M5' one, redo the NAV unit I got with a brand new one, and see if I can sell it and break even or perhaps minimize my loss. I'll then be left with the M5 monitor as a back-up.

Great thread and nice job by everyone figuring this stuff out.