BimmerFest BMW Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter #1
So my wife drives a 328i and it needed a new battery. So I took the battery out to get tested and to buy a new one instead of taking it to a dealership. I closed the trunk not thinking and now I can't open it. I've tried hooking up jumper cables to the terminal under the hood and nothing. Bmw is wanting to charge us $800 to break out a rear light to open it and replace the light which is freaking stupid. Im over this car cause it's had a lot of issues. Can any one please help... There has to be a way into the trunk!!!
 

·
Car guy since 1968
Joined
·
1,478 Posts
So my wife drives a 328i and it needed a new battery. So I took the battery out to get tested and to buy a new one instead of taking it to a dealership. I closed the trunk not thinking and now I can't open it. I've tried hooking up jumper cables to the terminal under the hood and nothing. Bmw is wanting to charge us $800 to break out a rear light to open it and replace the light which is freaking stupid. Im over this car cause it's had a lot of issues. Can any one please help... There has to be a way into the trunk!!!
Easiest way out is to get a charge into the battery so you can open the trunk...unless the rear seats fold down, in which case you can go in that way (hint, hint...)

If the battery is a lead-acid battery, get a good quality battery charger, connect it to the terminals under the hood, start it and walk away for 12 hours to get a charge in the battery.

If the battery is a gel type, you need a standard battery as a buffer. (Check the directions for charging Optima batteries online for specifics.) Here's what to do:

- Park a vehicle with a standard lead/acid battery next to the BMW. (Or pull a standard battery from another car)
- Connect jumper cables between the lead/acid battery and the charging terminals on the BMW.
- Now connect the battery charger to the lead/acid battery, and walk away for about 12 hours.

The lead-acid battery serves as a buffer and will allow the gel battery to take a slow charge.

If you don't own a good charger, get one. Every garage needs one.

PS: I did procedure #2 last weekend when I accidentally ran the Optima battery in my 280ZX flat. That's the way to charge a battery of that type when they get too low.
 

·
Car guy since 1968
Joined
·
1,478 Posts
My issue is there is no battery in the car and the trunk is closed
Do the back seats fold down? If so, access granted.
 

·
Car guy since 1968
Joined
·
1,478 Posts
Well, no more ideas here.

If it's any consolation at all, you're not the first to do this. Try searching the forums for info, as it has been discussed before.
 

·
Registered
Joined
·
3,335 Posts
http://www.e90post.com/forums/showthread.php?t=986670

Thread tells about finding the right wire, applying 6v (yes, it does NOT need 12v), and about applying the voltage by PIERCING the insulation with a conductive straight pin to make contact with the conductive interior of the wire to apply the 6v (and NOT stripping off insulation to get to the wire). One guy posts:

a) Take out the two torx screws just below the glovebox on the left and right to remove the panel below the glovebox. Disconnect the power socket and the light which are attached to the panel.

b) Below the fusebox there is a big flat horizontal junction box (Junction Box A4010). You can spot it easily because there are two big connectors going into it facing you. There is a flat wide connector plugging into the BACKSIDE of this same junction box. There are about a dozen small wires going into it and one big brown ground. This is the one you need to get to. (Connector X14270) Ideally, you'd want to disconnect this, but I could not manage to get it out from that position.

c) Identify the small wire which is gray with a stripe of green (it looks mostly gray). If you get the connector out, this is pin 12. It's the only grey/green wire in the bunch though.

d) You need to very briefly apply 12 volts to this lead to pop the trunk. I did it the ugly way - I very carefully razored off some of the insulation to expose it. Then I just attached some leads to my new battery. I stuck the ground lead into brown wire connector for the power socket I had disconnected when I removed the glove box panel. Then I just brushed the positive lead against the exposed pin 12 wire. The trunk popped instantly.

Now that I know what to do, I'll bet I could do this in 10 minutes. It's really just two screws to remove the pane and knowing which wire to power.​

Another guy follows with a post, "I just found the gray and green wire and used a 6volt battery and it worked!!!!!"
 
1 - 7 of 7 Posts
Top