Problem opening trunc without battery

[polvloesberg]

I have a BMW E60, 520d 2005.

The battery of the car was empty. I used jump start cables connected to another car, connected them in the motor compartment to open the trunc of the car and removed the old battery.

As I didn't have the new battery at hand yet, I closed the trunc to get the new battery.

However, upon return with the new battery, when I connect the jump start cables again, there is no way to open the trunc anymore, or to get any electricity in the car at all (i.e. radio, interior lights, dashboard lights, ...remain all dead with the jump start cables connected). When I measure the tension between the +connector in the motor compartiment and the chassis, I do measure some 14V, so that doesn't seem to be the problem. Without electricity, it is not possible to open the trunc.
Would it be possible that because of some strange reason, when the battery is not connected, the charging point in the motor compartiment is no longer connected to the rest of the electricity system in the car ? If so would injecting electricity through another point (cigarette lighter?) be an option ?
I'm quite sure the disconnected battery cables do not accidentaly connect to the chassis, as I wrapped them in some socks before closing the trunc.

My trunc does have a key hole to open it, though I don't have the key anymore.

I did some research on how to remove the backseats, though apparently one needs to unscrew some bolts from within the trunc...

Some 5 series models appear to have a cable under the backseat to open the trunc, though after removing the bottom part of the backseat, I did not find any cable (except for 2 electrical cables).

After searching a bit around on the internet, I found a vague reference to a possibility to put current on an electricity wire in the glove compartiment, though I wouldn't have a clue which wire or how to do this. Maybe putting current directly on the trunc opening button near the driver seat could also be an option ?

It's really a very stupid problem, though I'm completely lost for the moment. Hope someone can help ?

[joe_ali]

doesn't your remote has a key in it? I thought all key fobs had a key attached to them