Can't get in to the trunk, need help

[Desmo85]

So if you disconnect the battery you can not open the trunk, no matter if you feed it with external power supply - thats the conclusion.

Meaning that you need to connect the + and - with a short cable, so the circuit is closed.
Since the E89 is equiped with the IBM (Independent Battery Management) it migh be more complicated probably......but I will be trying to find out more about it.

[bobmos]

Ok, so this discussion had me running over to my storage garage to see if I could shed any light on the topic. Prior to storage my BMW shop foreman advised me to disconnect the battery and leave the trunk open. So I did that, backing into my space deep enough to discourage anyone from going back there, but still leaving me enough room to squeeze in and reconnect the battery in the spring.

Tonight I brought over my 535 and some jumper cables to see if the car would start using the under hood terminal with a disconnected battery. It would not. However, it did fire up the interior lights, and radio etc... My car has a button to pop the trunk, and when pushed I could hear the actuator responding. I did not go so far as to close the trunk and release it again as I still had a bit of trepidation from other posts on this topic, but it seems clear to me that the trunk would pop.

So, unless your car does not have the trunk release button, then you are safe.

[rking117]

Originally Posted by Zyal8r

Rking its actually our theory, See the post above yours.
At any rate, I hope it works

haha, i didnt read the entire post before i chimed in. sorry to rain in on your parade.

[rking117]

Originally Posted by bobmos

Ok, so this discussion had me running over to my storage garage to see if I could shed any light on the topic. Prior to storage my BMW shop foreman advised me to disconnect the battery and leave the trunk open. So I did that, backing into my space deep enough to discourage anyone from going back there, but still leaving me enough room to squeeze in and reconnect the battery in the spring.

Tonight I brought over my 535 and some jumper cables to see if the car would start using the under hood terminal with a disconnected battery. It would not. However, it did fire up the interior lights, and radio etc... My car has a button to pop the trunk, and when pushed I could hear the actuator responding. I did not go so far as to close the trunk and release it again as I still had a bit of trepidation from other posts on this topic, but it seems clear to me that the trunk would pop.

So, unless your car does not have the trunk release button, then you are safe.

This is perfect and what i was hoping would happen. There have been so many post on this issue that something had to give somewhere. So now we know that you have to get jumped by another BMW. (HAHA just kidding)

[Zyal8r]

Originally Posted by bobmos

Ok, so this discussion had me running over to my storage garage to see if I could shed any light on the topic. Prior to storage my BMW shop foreman advised me to disconnect the battery and leave the trunk open. So I did that, backing into my space deep enough to discourage anyone from going back there, but still leaving me enough room to squeeze in and reconnect the battery in the spring.

Tonight I brought over my 535 and some jumper cables to see if the car would start using the under hood terminal with a disconnected battery. It would not. However, it did fire up the interior lights, and radio etc... My car has a button to pop the trunk, and when pushed I could hear the actuator responding. I did not go so far as to close the trunk and release it again as I still had a bit of trepidation from other posts on this topic, but it seems clear to me that the trunk would pop.

So, unless your car does not have the trunk release button, then you are safe.

This is important news for anyone that stores their Z4 and most of us do. I will send a prvt message to the OP. It should be archived or sticky??

[sjeupie]

Originally Posted by bobmos

Ok, so this discussion had me running over to my storage garage to see if I could shed any light on the topic. Prior to storage my BMW shop foreman advised me to disconnect the battery and leave the trunk open. So I did that, backing into my space deep enough to discourage anyone from going back there, but still leaving me enough room to squeeze in and reconnect the battery in the spring.

Tonight I brought over my 535 and some jumper cables to see if the car would start using the under hood terminal with a disconnected battery. It would not. However, it did fire up the interior lights, and radio etc... My car has a button to pop the trunk, and when pushed I could hear the actuator responding. I did not go so far as to close the trunk and release it again as I still had a bit of trepidation from other posts on this topic, but it seems clear to me that the trunk would pop.

So, unless your car does not have the trunk release button, then you are safe.

Just to make sure I don't get my hopes up for nothing: you disconnected the battery completely. As in: + and - terminals disconnected?
I really hope that this is going to do the trick. I had my car sinc 4 days and never noticed a trunk release button, a part from the one on the remote. Hopefully that does the trick nonetheless. Thank you very much for checking!

Originally Posted by Zyal8r

This is important news for anyone that stores their Z4 and most of us do. I will send a prvt message to the OP. It should be archived or sticky??

This is indeed very important news. The OP 'fixed' his problem by breaking through the center compartment but other people all over the world, including me, face the same situation. So to summarize our conclusions so far:

In case of disconnected battery (- or +) and shut trunk:

Does not work:
- connecting a battery charger to terminals under hood
- cry

Does work.
- connecting an 'old school charger' to terminals under hood (vehicle could start if + is connected. Otherwise only low voltage circuit)
- connecting jumper cables connected to another vehicle, to terminals under hood (vehicle could start if + is connected. Otherwise only low voltage circuit)
- break into the trunk through the center storage compartment.
- move with controlled violence the trunk lid 5mm to the left till it unhooks on the right side and then again 5mm to the right so it unhooks on the left side. This will off course put a lot of strain on the hinges etc. Do at own risk.

Am I correct in my above assumptions?
Is anybody willing to go out of his way and double check the 'jumper cable with battery disconnected' theory? I'll do it for sure and report back when I'm back at my car in a couple of months (heck, I'm going to buy some pro-jumper cables for it just so we can avoid any doubt on that as well in case it doesn't work, cause sometimes I can't jump a car if the battery is completely dead because of the resistance in my 'cheap' jumper cables) but maybe somebody wants/needs to do it before that.

Ps: it is incredible to see so many people are willing to help out here and keep digging!

[bobmos]

As I have with my previous summer cars, I disconnected both terminals completely from the battery. I hope that doesn't create any kind of issues once I reconnect them...

[Desmo85]

Originally Posted by bobmos

As I have with my previous summer cars, I disconnected both terminals completely from the battery. I hope that doesn't create any kind of issues once I reconnect them...

Well you could run into problems.....newer BMW´s have the so called IBM (Independent Battery Management) which is kind of a registration of the battery to the car. Meaning that in worst case your car would not recognize your battery when you reconnect it, and would not load energy in it while driving. You would however get a warning in the dashboard if it fails to recognize the battery.
It happend to me with my 530D when I changed the battery (damn you programmable park heating)I had to go to the dealership which had the battery registrated and of course charged me for it.

[rking117]

Originally Posted by Desmo85

Well you could run into problems.....newer BMW´s have the so called IBM (Independent Battery Management) which is kind of a registration of the battery to the car. Meaning that in worst case your car would not recognize your battery when you reconnect it, and would not load energy in it while driving. You would however get a warning in the dashboard if it fails to recognize the battery.
It happend to me with my 530D when I changed the battery (damn you programmable park heating)I had to go to the dealership which had the battery registrated and of course charged me for it.

I am pretty sure that once programmed to a battery that is the only thing you need to do. The only thing i can think of from there is if the battery while disconnected goes out of tolerance in Voltage or Amperage and does not recover after a charge.

[Zyal8r]

As long as you are going to disconnect both + and - , why not take the battery out completely, take it home and put it on a good trickle charge? Battery life can be greatly extended with a good trickle charger because it reduces the sulphating to almost none. Of course if you have A/C in the barn just hook it up there and leave everything connected.

[sjeupie]

Originally Posted by Zyal8r

As long as you are going to disconnect both + and - , why not take the battery out completely, take it home and put it on a good trickle charge? Battery life can be greatly extended with a good trickle charger because it reduces the sulphating to almost none. Of course if you have A/C in the barn just hook it up there and leave everything connected.

Never thought of that really.
I still have difficulty though understanding the difference between disconnection only the -, only the +, or both.

[gbell210]

Question for those that did disconnect the battery or the battery went completely dead. How did you open your door, without power to the window? Is there enough give in the window seal that you can force the door open and not break the glass?

I don't have a problem with mine at the moment, but while reading this, no one ever mentioned a problem with window automatically lowering when you opened the door. That is the one thing I worry about, to get into the car so I could get into the engine bay for the terminals.

[Desmo85]

Originally Posted by gbell210

Question for those that did disconnect the battery or the battery went completely dead. How did you open your door, without power to the window? Is there enough give in the window seal that you can force the door open and not break the glass?

I don't have a problem with mine at the moment, but while reading this, no one ever mentioned a problem with window automatically lowering when you opened the door. That is the one thing I worry about, to get into the car so I could get into the engine bay for the terminals.

Opening the door is not an issue but closing is.

[sjeupie]

As Desmo said, opening the door is not an issue (luckily I left the small rear windows open so I could unlock the door manually as my manual key did not do anything!).

I heard that the auto lowering system can get confused though. My car is still without power ever since so I do not know what will happen yet.

[sjeupie]

Ok, so last week at Easter I went to see my Z4. As my cheap set of booster cables have left me Diesel Land Rover stranded once as they were not powerfull enough to get it up and running again, I bought a professional set of jumper cables to eliminate that possible problem. FYI I went with 4.5m long, 35mm 700A cables with pure Brass clamps.

Hooked my Z4 up to a 150hp petrol Toyota engine and this what happened:
- instantly enough juice to simply open up the trunk and connect the battery again, despite having disconnected the +.
- Sat in the car, lowered the side window myself, closed the door, raised the window again myself and after that the window lowered and raised itself again automatically when opening and closing the door.
- Clock is reset

As my insurance is temporary still on hold for winter, I am not allowed to drive the car till next week. I have therefore not yet tried to start the car to save the remaining juice in the battery and because it makes no sense to start a car and leave it running for 10 minutes only. So I'll report back on the starting of the engine in a week or so.

You guys have no idea how good I felt when the trunk simply opened up...pffff! Just in case, I've unhooked the center console tray (ski-hatch thingy). It are two simple plastic attachments on the top of the hatch inside the trunk. So in case you'd want to break into the trunk through the cabin, you'll have to hit the top of the panel.

[sjeupie]

So final update on the closed-trunk battery thing:

Got back to my car which was standing still since 3 months with a disconnected battery and since 1 week with a connected battery. Fired her up without any problem. Set the date and time and made a 7 hour drive. All works fine.

Yesterday washed her inside out (I think the previous owner had a dog....or a very hairy girlfriend..!), clayed the exteriour and gave her a nice layer of wax, buffed it out till both my arms went numb but boy does she shine on the driveway now!

[Lurcher]

Welcome back to spring

[Aliquantus]

Digging up this old thread since I did this yet again tonight. I've been able to pull the release a few times with a long bar but this time I had the top down so it's impossible to get to that. Luckily I just unhooked my negative cable and even though I couldn't reach the cable to reconnect, I was able to use a jumper cable from the battery post through the ski hole to ground on the seat mount bracket. Powered right up. Whew.

Just one more suggestion to add to the thread.

[RobbiZ4]

Another tip:

The trunc lid motor can be started by an external power supply directly from the fuse box / junction box below the glove box even when the battery got disconnected or completely removed. It takes about 2A.
If that's an option for you, come back to me and send a PN.

Originally Posted by sjeupie

And only in the US I believe. I never checked (and currently can't ) but I believe the EU versions have got no lever.

Side note:
Only the US cars seem to have the "emergency trunk lid lever" mounted, none of the European cars.

And just another side note:
not every Z4 has a "ski hole" to get into the compartment.

[Aliquantus]

Originally Posted by RobbiZ4

Another tip:

The trunc lid motor can be started by an external power supply directly from the fuse box / junction box below the glove box even when the battery got disconnected or completely removed. It takes about 2A.
If that's an option for you, come back to me and send a PN.




Side note:
Only the US cars seem to have the "emergency trunk lid lever" mounted, none of the European cars.

And just another side note:
not every Z4 has a "ski hole" to get into the compartment.

Interesting, hadn't seen that suggestion before. I'll have to remember that next time I do this since I've been replacing a few airbags and generally like to disconnect the power just in case.

[RobbiZ4]

Originally Posted by Aliquantus

Interesting, hadn't seen that suggestion before. I'll have to remember that next time I do this since I've been replacing a few airbags and generally like to disconnect the power just in case.

If disconnecting the battery is a planned activity, you can simply block the trunc lid according to the following video:

E89 block the trunc lid for maintenance

Block it before you disconnect the battery.

[tIndy]

I was speaking to a sales guy at a local auto parts store. He suggested using a cigarette lighter battery charger to power the car until the battery has enough charge to open the trunk.

Does this work for the z4?