Open the drivers door, then go to the boot and wait, the red led on the nav computer will flash several times, wait until it goes out, then disconnect the 2 plugs (purple and blue) then the GPS plug (be careful is easy to break), wait 10/20 seconds then reconnect gps, then the 2 plugs (purple and blue), hopefully the computer should spring back into life, if not then it's dead.

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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.