[sekitori]

Just above and to the right of the rear license plate on my 2009 328i sedan is a lock. It's located parallel to the ground in the overhang just over the plate and because of its position it's difficult to access when the trunk lid is closed. Using the key has no effect on opening the trunk lid. The position of the switch in the glove compartment makes no difference. The key won't open the trunk lid whether it's locked or unlocked.

The owner's manual states that the key opens the glove compartment and the driver's door but it says nothing about the trunk. In fact, the manual doesn't seem to acknowledge that there even is an exterior trunk lock.

The reps at my BMW dealer don't know what the lock is used for. I have a friend who has sold BMW's for a long time. He's extremely knowledgeable but he also doesn't have any idea about its purpose. He seems to think that it may be involved with European models but he's not sure.

Since I can open the trunk lid (or as BMW calls it, the "luggage compartment lid") with the button inside the car and with my remote, I really don't need an external lock. But it would be nice to know why it's there. Any ideas?

[JL330i_UT]

i know the lock on my "luggage compartment lid" is there in case of emergencies, like if the battery dies and i need to acces the "luggage compartment".

[Boost3dm3]

how hard did you turn the key? mine was pretty stiff to open the trunk.

[piezo]

I retract my earlier version of this post. The '09 version of the E92/3 manual has been reworded; they expect you to take it to a dealer (or correspondingly trained shop) in the event of malfunction.

Then why even bother installing a lock cylinder in the first place?

[walsh]

Its in case your battery dies. your battery is in the trunk... i know there is jump start terminals under the hood but regardless... If your battery is dead the automatic trunk pops on the remote, in the car, and on the trunk handle will not work so you use your key in this lock to open it... you need to turn it pretty hard.

[dunit]

The lock is hard to use,and the key is small. I found if you press down on the trunk while turning the key it will help it to unlatch . You have to turn hard ,as the lock operates linkage to unlock the latch.

[AlanQS]

Our versions do not have internal buttons for the trunk. Where are yours situated?

[sekitori]

Originally Posted by bwalshy99

Its in case your battery dies. your battery is in the trunk... i know there is jump start terminals under the hood but regardless... If your battery is dead the automatic trunk pops on the remote, in the car, and on the trunk handle will not work so you use your key in this lock to open it... you need to turn it pretty hard.

Thank you for the explanation. Using that lock to access the trunk when the battery is dead makes a lot of sense. I now see why it can be a very valuable feature. My question is this. Since the lock is so important, why is there no mention of it in the owner's manual? I would think that BMW would come up with some explanation as to its presence and its use. It would only take a few lines of print and maybe a small diagram to explain everything.

I'm beginning to think that manufacturers who produce excellent cars don't always equal that excellence in their owner's manuals.

[piezo]

let me take another crack at this...

The ability to open the trunk with the key has been removed from the versions of the '09 owner's manuals currently available on bmwusa.com. The OP described the presence of a lock cylinder which the key doesn't fit. A couple of scenarios come to mind; the installation of the lock was a logistical assembly error -or- the dealers have master keys for the aforementioned malfunctions. My money's on the former. Perhaps someone with access to the latest technical material could enlighten us?

AlanQS, the internal trunk release switch is on the outboard side of the driver's footwell, just above the diagnostic connector cover.