My 07' S550 has keyless entry. The problem is that the drivers rear door will not open sometimes. One out of 6 times I can pull the handle and it will open. The keyless sensor seems to be working because I can touch the handle and it will unlock but when I pull the handle the door will not open. The door will open from the inside handle just fine. Plus, this is the only door that this is happening on. When I pull the handle it's like the latch is not releasing. My MB indie wants $1200 to replace the handle! Says they have to take the door completely apart. Looking for infant ideas. Thanks in advance.