Normally, it is advised to disconnect your car battery when one is not going use the car for a longer period. This is to prevent the battery getting drained and the car becoming useless upon your return.
Particularly with the BMWs without a manual lock, the Boot/Trunk comes with an electrical latch which can only be opened with its remote.
This means, once you disconnect the battery and close the Boot/Trunk, there is no direct way to open it when you want to reconnect the battery wire/lead.
I have seen many videos showing drilling hole through the rear seats to reach the latch from the inside of the car. There is no need to go to this extreme because BMW provides a very easy indirect way to open the Boot/Trunk even if car’s own battery is disconnected. Please let me explain with some photographs.
All you require is 12V DC battery, ideally another car battery. This does not have to be a brand new one but atleast which can provide a small amount of current to drive the electrical latch of the Boot/Trunk. Even a portable jump starter should work.
I chose to use an old used 12V car battery which I had to replace with new one because it had become weak and could not start my car’s diesel engine. I think any other 12V DC battery with sufficient current capacity should also be able to open the Boot/Trunk as I think it does not have to be a car battery. The following photo shows the old car battery that I had used.
I hope you know how to open the driver side door manually using the physical key from the key fob. Then open the car bonet. The next thing you have to do is to locate a red capped protuding connector looking thing in your BMW’s engine bay as shown with an arrow in the following photo:
In fact, this connector is a positive terminal of the Car’s power supply. The body is a negative terminal. So, connect these car terminals to the battery terminals as shown in the following photo:
After these terminals are connected, now you can press your remote key fob boot/trunk open button. This should open the electrical latch of the boot and now you can open the boot/trunk as shown in the following photo:
Now, after you have opened the boot, first disconnect this external battery. Then reconnect the car’s own battery. If everything else is ok, then your car should function normally.
