First off, welcome to the forums.

Second, BMW and Cheap don't go together.

It sounds like either the nav computer is kaput or the TV module (if you have one).

Disconnect the TV module and see if the nav comes back, if not disconnect the nav and reconnect the TV and see if you get the menu on screen.

mk2's are cheap as chips and personally i'd go for a mk3 or mk4, as the mk2 is very dated now.

If its the TV module then 4:3 ones are dirt cheap, $80 should get you one.

HTH

P.S try looking at the plugs on the back of the units as they may be loose (it's worth a shot).

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Sept 03, M3, Silver Grey. Retro-fits: Modded Mk4 DVD Drive, OEM Bluetooth, VR Control, Rainbow Speaker Upgrade, Sony SOT Amp, HK Sub, CCFL, Intravee II, NightMode.