It's very common failing motor only works one direction so only unlocks would be a normal failure.

If you sit in the back and hit the key fob lock but then push the lock button the door handle should do nothing. Key fob press unlock driver door should unlock and the other three should activate so the inside handles work.

If that's the case with RR, You've determined that the primary lock motor only works in the unlock direction which is the most common failure.

Search awr-fix with my username I wrote a $12 repair vs. $240 replace guide.

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)