So now my right back door is troubling me...

When i lock the door normally by pressing once on the key, all is good (all the doors lock)

When i press twice on the key, to lock the door, my rightside backdoor unlocks (all other doors remain locked)

But then again when i press lock, it locks all doors again...

Also when i lock the doors from inside (the lock-button on door), all doors lock, except rightside backdoor.

Where to start the trouble-shooting ?

-Alex

Possibly water getting into the connector on that door? I would start there first because its free to do lol, try locking and unlocking with the door card and membrane off and see if you can see anything