Could be the direction you are turning the key.

Or could be a fault in the system. I found that the system has a built-in fault protection circuit. I had some trunk issues too. After pulling the battery for a while all was well again. If the system is without power, it will reset.

If there is still an issue, then its a problem with the mechanism.

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1991 560 SEL / 185k miles
1992 750il / 17k miles - project car