I'm guessing broken dhc so handle not working, explain why doors don't open from outside.

If you have a trailer hitch, factory hitch power has an always live pin that will work to back feed power.

Often when battery completely dead your key remote will lose pairing so you still might not be able to get in.

Getting the hood open method is documented you usually have to cut a hole in the panel surrounding the radiator.

Odds are good key fob wont be working even if you get power to the battery you will need to use traditional method to locksmith your way in.

Bend the door with an air wedge and a stiff rod to push the central lock button to undo the double lock then a very long rod with hook to pull the door handle from the other side to open the door.

If passenger door dhc ok you only have to pull once to unlock which is easier that second pull to unlatch is a lot of force not easy with a rod.

If you don't have factory hitch you might have a harness with power you can with any luck find the power pin with DMM there should be a few volts at the least.

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