The key FOB for my Mercedes GLK350 keeps draining the batteries. I just changed them out and about a week later the signal light to change FOB battery came on - has done this several times now and I keep changing batteries but it just happens again and again. I am using Duracel CR2025 3V disk - I noticed that Mercedes uses Panasonic. Anyone know what could be causing this issue.....SAM problem maybe? Thanks.