[John 070]

Originally Posted by ctuna

Not a good idea to use battery back up in these .
It blows fuses and doesn't save anything worth saving.
Also it a mess to do because of the 5 hot +12 wires you
are dealing with on the stupid battery distribution block.

Good tip for when one day I do the 335i. The weakest link in such a job can simply be something slipping, then there's an electrical problem.

With my wife's GM SUV the battery is under the rear right passenger's feet--I've been tempted to do work without disconnecting it, but told myself, do it right (her car takes 800+ miles before the emissions go into a ready state). There's a job where the top strut engine mount has to have the main electrical box pulled aside--it did cross my mind to leave the battery connected to save time, but I didn't....

[EssexAl]

Just done the same silly today with my '13 E93. No keyhole, disconnected the battery, shut the boot. Queue the pain. Some pics of the bypass

View post on imgur.com

[Archaeologistt]

Great post, hope I never need it...

[berdavid88]

Originally Posted by eMarcus

ctuna's isntructions worked! See post #14 on this thread. Thanks for the solution! And credit to my wife for finding this post.

To build on it, I figured out how to do it without having to strip a wire, or anything else invasive. This should also save you the uncertainty of hunting down the infamous grey wire with green stripe amidst bundles of wires. I'll post a video later. Note: I was working on a 2011 328i with a disconnected battery and a locked trunk.

If you're a layman like me, don't be intimidated by any of this. It's very doable. I'm not a mechanic or an electrician, so please pardon what is likely my ignorance of many things. I just want to be more helpful than "put your key in the keyhole and turn".

The goal is to be able to pull out the junction box ("A4010") to disconnect and access the backside connector ("Connector X14270"). Everything on a BMW seems to work like a Japanese puzzle box, so you need to do these things in order and reverse it when you put it back together.

You'll need a torque screwdriver, a phillips-head screwdriver, 1-2 feet of radio wire, and a 9-volt battery. Electrical tape, 1 small wire clamp, and a plastic prying tool are handy too.

1. Per ctuna's reply on this string (#14, line 4a), remove the bottom panel below the glove box.

2. Remove both cup-holders above the glove box. This is necessary for the glovebox to pull out (next step). You'll need to pop out the plastic trim around the cup-holders. Use a plastic prying tool if you have one, otherwise a flathead screwdriver will work - just be very careful not to scratch the trim or your dash. It should give easily; just pop one side and pull the rest out gently with your fingers. There should be 4 screws. After taking them out, the cup-holders should pull right out.

3. Remove the glove box. I think the reason ctuna couldn't manage to pull the junction box is because the glovebox locks it in. Open the glove box and there should be 6 screws. Once they're removed, the box should pull right out. Disconnect the connectors of whatever electronics are hardwired into it. I just had a USB charger and the glovebox light. Now you should have full view of your fusebox and the flat junction box below it.

4. Disconnect the junction box. First, disconnect the two wire connectors facing you (one blue and one black) and secure them out of your way. Next, there are 2 screws on the left and the right of the plastic "sleeve" holding the junction box secure. After you unscrew them, there's a plastic tab on the top of the box near the left screw. You'll have to feel around and press it down to unsecure the box and be able to pull it out. Note: You shouldn't be able to pull it all the way out - nor should you just yet.

5. Once you have the junction box loose, disconnect the wire connector behind it. This is the trickiest part. On the far right (as you face it from the seat) on the back of the box is a tab. Slide it all the way out to the right. It might take firm force at first. That should cause the connector to pull away from the box. And there you have it! That connector is the Grail. Pull out the junction box completely and set it aside.

6. Locate the correct pin hole (pin #12) on the connector for the trunk release. You'll notice the junction box has corresponding pins to send electric signals down these small square holes. On the connector, you'll notice the top row of holes has a "1" on the far right, and a "20" on the far left. Just count right-to-left to the 12th hole in the top row. On the other side, you should see the infamous grey wire with a green stripe. It's almost dead-middle of the connector.

7. Send a small electric current down this hole. I used a 9-volt battery and thin radio wire (usu. 2 very thin intertwined wires with a red and a white insulation for positive and negative respectively). To ground it, I wired the negative lead of the battery to a small clamp (with my white wire) and attached the clamp to the passenger seat rail. Now, I was paranoid here not to let your positive and negative wires touch each other or the same piece of metal for fear of shorting or burning something out. It's just a 9-volt battery, but better safe than sorry. Next, before attaching the other (red) wire to anything, I stripped about an inch of insulation off one end and shaved the wire thinner with a knife. You should then be able to slide that end of the (red) wire into pinhole 12. Be careful and don't force it; you don't want to end up with a broken piece of wire jammed into that hole. Once that end of the (red) wire is secured into pinhole 12, just brush the other end of it against the positive lead of the battery.

If all goes well, you should hear the beautiful sound of your trunk latch releasing and a weight of embarrassment (for getting yourself into this mess) lift from your shoulders.

PS - Just in case, fold down your back seat when you're done.

Ok. So I got registered here just to say thank you. Thanks for Ctuna for the original post and also big thanks to eMarcus for giving an even more detailed description. With that method taking off the globe box, it was a piece of cake. Actually I can’t believe I pulled this out. At first I thought it would be much more difficult. I was stuck like many here. Took out the battery and couldn’t open the trunk. I have an e92. To fold the rear seats you have the buttons in the trunk. Jump start also didn’t work with the battery disconnected. Had no idea what to do. I found a cheap rear shelf on ebay. Thought I will cut a hole in my rear shelf so I get access to the buttons to fold down the rear seats and put back the battery that way. But this method man. Can’t tell how happy I was when I connected the cable to the small battery and I heard the noise of opening the trunk. What a f***ing annoying thing that you can’t open the trunk other way but lesson learned, will be careful next time and even if not, with this method it’s not that bad. I feel like James Bond or something for pulling this off. Thanks again.

[Miner38]

Originally Posted by eMarcus

ctuna's isntructions worked! See post #14 on this thread. Thanks for the solution! And credit to my wife for finding this post.

To build on it, I figured out how to do it without having to strip a wire, or anything else invasive. This should also save you the uncertainty of hunting down the infamous grey wire with green stripe amidst bundles of wires. I'll post a video later. Note: I was working on a 2011 328i with a disconnected battery and a locked trunk.

If you're a layman like me, don't be intimidated by any of this. It's very doable. I'm not a mechanic or an electrician, so please pardon what is likely my ignorance of many things. I just want to be more helpful than "put your key in the keyhole and turn".

The goal is to be able to pull out the junction box ("A4010") to disconnect and access the backside connector ("Connector X14270"). Everything on a BMW seems to work like a Japanese puzzle box, so you need to do these things in order and reverse it when you put it back together.

You'll need a torque screwdriver, a phillips-head screwdriver, 1-2 feet of radio wire, and a 9-volt battery. Electrical tape, 1 small wire clamp, and a plastic prying tool are handy too.

1. Per ctuna's reply on this string (#14, line 4a), remove the bottom panel below the glove box.

2. Remove both cup-holders above the glove box. This is necessary for the glovebox to pull out (next step). You'll need to pop out the plastic trim around the cup-holders. Use a plastic prying tool if you have one, otherwise a flathead screwdriver will work - just be very careful not to scratch the trim or your dash. It should give easily; just pop one side and pull the rest out gently with your fingers. There should be 4 screws. After taking them out, the cup-holders should pull right out.

3. Remove the glove box. I think the reason ctuna couldn't manage to pull the junction box is because the glovebox locks it in. Open the glove box and there should be 6 screws. Once they're removed, the box should pull right out. Disconnect the connectors of whatever electronics are hardwired into it. I just had a USB charger and the glovebox light. Now you should have full view of your fusebox and the flat junction box below it.

4. Disconnect the junction box. First, disconnect the two wire connectors facing you (one blue and one black) and secure them out of your way. Next, there are 2 screws on the left and the right of the plastic "sleeve" holding the junction box secure. After you unscrew them, there's a plastic tab on the top of the box near the left screw. You'll have to feel around and press it down to unsecure the box and be able to pull it out. Note: You shouldn't be able to pull it all the way out - nor should you just yet.

5. Once you have the junction box loose, disconnect the wire connector behind it. This is the trickiest part. On the far right (as you face it from the seat) on the back of the box is a tab. Slide it all the way out to the right. It might take firm force at first. That should cause the connector to pull away from the box. And there you have it! That connector is the Grail. Pull out the junction box completely and set it aside.

6. Locate the correct pin hole (pin #12) on the connector for the trunk release. You'll notice the junction box has corresponding pins to send electric signals down these small square holes. On the connector, you'll notice the top row of holes has a "1" on the far right, and a "20" on the far left. Just count right-to-left to the 12th hole in the top row. On the other side, you should see the infamous grey wire with a green stripe. It's almost dead-middle of the connector.

7. Send a small electric current down this hole. I used a 9-volt battery and thin radio wire (usu. 2 very thin intertwined wires with a red and a white insulation for positive and negative respectively). To ground it, I wired the negative lead of the battery to a small clamp (with my white wire) and attached the clamp to the passenger seat rail. Now, I was paranoid here not to let your positive and negative wires touch each other or the same piece of metal for fear of shorting or burning something out. It's just a 9-volt battery, but better safe than sorry. Next, before attaching the other (red) wire to anything, I stripped about an inch of insulation off one end and shaved the wire thinner with a knife. You should then be able to slide that end of the (red) wire into pinhole 12. Be careful and don't force it; you don't want to end up with a broken piece of wire jammed into that hole. Once that end of the (red) wire is secured into pinhole 12, just brush the other end of it against the positive lead of the battery.

If all goes well, you should hear the beautiful sound of your trunk latch releasing and a weight of embarrassment (for getting yourself into this mess) lift from your shoulders.

PS - Just in case, fold down your back seat when you're done.

Thank you thank you thank you. tried everything but this was the one that got my boot open. i was getting close to crowbar option but this saved the day. thank you

[LCI-E92-N55]

Just wanted to report in and say I tried eMarcus' instructions and they worked.

I'm in Australia and the parts used were from Bunnings:
4008496639540 BATTERIES 9V VARTA
9311644113423 TAPE INSULATION PVC DETA
2443004000009 CABLE ELECT BELL WIRE P/M

I bought alligator clips but didn't end up using them.

We had to thin the gauge of the wire a bit as initially we didn't get anything. We also had to attach the neutral to a raw metal piece on the seat rail as attaching to the rail itself didn't seem to work. In the end it's not a super tricky fix but of course the best way is to prevent the boot from closing by flicking the latch shut and/or putting a towel down so it can't latch close.

Jump starting or direct connecting to battery did not work as we disconnected the battery completely when the boot had closed.

Initially I was very hesitant to try but this was the last option before having to get the car towed. eMarcus' post saying not to be intimated was comforting - I was concerned I could have fried something and make things go from bad to worse but thankfully everything eventually came good

[sonnydelight]

Just wanted to check in and say that eMarcus’ instructions worked perfectly for my 2009 e90 M3! Thank you!!