The battery for the E420 is located in the trunk of this vehicle, not near the firewall or under the hood. and if it is the fuel relay, is this under the dash board that you are talking about, and if it is just about where under the dash is it located.?? I surly appreciate your reply, do you know where I maight get a diagram of the position of this fuel relay and of course the part number if it is available. Thanks a lot for your reply. Ben