1998 bmw 528i battery died how to open trunk. cant get in with the key

If the battery is under the back seat like some models, charge battery.

Ignition key works the manual door lock:
You get out the original fob... pull out the (metal) key... insert it into the single lock slot under the drivers side door handle...
and twist like an old fashion key lock.





1998 bmw 528i key with dead fob Bing video

Reconnect a battery or use jumper cables from another vehicle then open the trunk.

get a battery

you should be able to tip the rear seat you should be able to trip the lock but check for a release cable around the rear deck, much easier

climb in through the back seats with a torch and trip the boot from inside

You can get back into the trunk, this is tricky but i have done a few times use the key in the trunk key hole and turn key one way all the way and then turn the other way while slightly lifting on trunk.

try it a few times it is tricky but trunk will open, there is something about the way the lock is set up due to it using battery voltage to open it, but with out battery it is funny, do not give up, turn key all the way both ways, the key will turn a little further to the left i think to open trunk. good day. let me know the out come.

The fuse is the first thing to check, If that is not it, you will probably need to replace the actuator on the trunk lock.

I am not familiar with this car, but most with electric locks can be unlocked the old fashioned way by placing the key in the lock and turning. Barring that, call for a wrecker or locksmith to open the car, or somehow get power to the electrical system to power the locks. If the hood is open, or openable from the outside, just use jumper cables to apply power. Perhaps you could get to the starter feed cable (or even the batter feed) from underneath the car. I hope this gives you some idea that is helpful in resolving your problem.

you have to stick the key in the trunk and unlock the trunk to get the gas door open!