The cable between the 2 locks is most likely to be giving problems. Take each lock out, lube it and make sure it's working properly.
Haha, I really should have said take BOTH locks out, the intermediate cable and the one leading to the main one, put it all on the bench and go from there. You might just have to shorten the jacket on the intermediate cable.

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1988 325is (purchased new) sold
2004 X5 3.0 2005 X3 2.5
2008 X5 3.0 (new to me)