[f80clone]

Thank you guys for real fast responding, will dig into this tomorrow

[chiefneil]

When you do get it sorted out, in the future don’t charge the battery directly. Use the charging post under the hood so the car knows the battery is being charged and adjusts accordingly.

[metallicpea]

That' strange, I did exactly this during winter storage one year on my E82 135i. Called BMW customer Service and their recommendation was to attach power to the jumper terminals under the hood. I though this wouldn't work with the battery circuit open, but it worked just as they said it would.

[Billfitz]

Originally Posted by metallicpea

their recommendation was to attach power to the jumper terminals under the hood. I though this wouldn't work with the battery circuit open, but it worked just as they said it would.

+1. Supplying power at the jumper terminals should power up the car systems.

[kern417]

Originally Posted by Billfitz

+1. Supplying power at the jumper terminals should power up the car systems.

I'm not sure about the wiring system in our cars but that would be a huge design flaw if it wasn't true. All wiring should stem from the fuse box, but if his didn't work then that implies it's all connected to the battery.

I've also clamped +power onto the starter to get power to another car with a similar issue but the battery was locked in the trunk. Not sure where our starters are though. Probably not nearly as accessible as a fwd car.

[Billfitz]

The battery supplies power to the fuse boxes of course. The question is does the positive charging post also connect to the fuse boxes, in a parallel connection with the battery positive connection. Logically it should. Even if the OP had disconnected the battery completely voltage at the charging posts should power the fuse boxes. Since he only disconnected the ground (Why? 'tis puzzlement) lug it's really odd that power to the posts doesn't power the car.

The starter is in more or less the same place on all cars. Typically the battery connects directly to the starter solenoid, through a very large gauge cable because of the high current involved, so if the battery is hooked up there's always voltage at the starter. It's only when the solenoid is energized by the starter button circuitry that power goes to the starter motor windings.

[f80clone]

when all this happened, i was not able to get power through the under hood positive and negative terminals for some reason, i had everything plugged right and jumped from another car and nothing...

Anyways problem is solved, took the rear seat out (really not that hard), and crawled in the trunk to open it, and i realized my seats do not fold down at all

[IK6SPEED]

Originally Posted by Billfitz

+1. Supplying power at the jumper terminals should power up the car systems.

-1

Google is your friend.

As multiple threads over 10 years all over bimmerpost and other bimmer forums report, this does NOT work.

I DID Google it before telling him to take out seats last night.

[metallicpea]

Originally Posted by IK6SPEED

-1

Google is your friend.

As multiple threads over 10 years all over bimmerpost and other bimmer forums report, this does NOT work.

I DID Google it before telling him to take out seats last night.

I don't follow... I see it working here, and I did it myself on my E82. What am I missing?

[Billfitz]

Originally Posted by metallicpea

I don't follow... I see it working here, and I did it myself on my E82. What am I missing?

I guess he didn't google it first.

[IK6SPEED]

Originally Posted by metallicpea

I don't follow... I see it working here, and I did it myself on my E82. What am I missing?

As noted, OP tried early yesterday and it did not work.

As also noted, dozens of threads on bimmerpost and other bimmer forums where this did not work. Many about the E Series. In other words, it is not a solution that often works. Unless you dismiss all the other threads as well.

Originally Posted by Billfitz

I guess he didn't google it first.

Perhaps you really should read what’s posted as OP had stated he tried that prior to your post.

What’s the definition of insanity?

Doing the same thing over and over while expecting different results.

[Billfitz]

I read what was posted, and I saw what I saw. So what was that video, fake news?

[IK6SPEED]

Originally Posted by Billfitz

I read what was posted, and I saw what I saw. So what was that video, fake news?

OK, I’ll take you at your word you can read. You just have a comprehension issue.

[metallicpea]

Originally Posted by IK6SPEED

As noted, OP tried early yesterday and it did not work.

Yes, I understand OP tried this. I do read the thread before I post.

It's curious this is the intended method by BMW and it works sometimes and not others. It might be useful for others if we figured out why this is. OP already got it opened, so only useful for others who read this in the future.

I am attempting to be constructive and avoid the typical smug internet forum responses. They are not helpful or entertaining.

[IK6SPEED]

Originally Posted by metallicpea

Yes, I understand OP tried this. I do read the thread before I post.

It's curious this is the intended method by BMW and it works sometimes and not others. It might be useful for others if we figured out why this is. OP already got it opened, so only useful for others who read this in the future.

I am attempting to be constructive and avoid the typical smug internet forum responses. They are not helpful or entertaining.

Neither is info where there are dozens of threads stating it does not work.

One might get lucky, but based on the threads over 10 years where this method was recommended and subsequently failed, the odds are not very good.

[jgoens]

Even though the issue is over I will add what I know: I did this on my e90 and what did work was hooking up a quick charger to the terminals under the hood. Powered right up and trunk was able to open.

[bimmer456]

Originally Posted by jgoens

Even though the issue is over I will add what I know: I did this on my e90 and what did work was hooking up a quick charger to the terminals under the hood. Powered right up and trunk was able to open.

Yeah a trickle charger won't work current too low. But jump starting should work if a quick charger works. could be the F30 terminal is different somehow and the electrical system uses some sort of power distributor over the positive terminal in the trunk to send power to various components using different cables attached to it. Though I thought the E90 was similar.

[f80clone]

Originally Posted by bimmer456

Yeah a trickle charger won't work current too low. But jump starting should work if a quick charger works. could be the F30 terminal is different somehow and the electrical system uses some sort of power distributor over the positive terminal in the trunk to send power to various components using different cables attached to it. Though I thought the E90 was similar.

Yep, tried a few supplies with power and even my brothers big jump box (for car haulers), no luck , and as IK mentioned ive seen a number of posts where this did not work so i was not shocked as i figured this works time to time, not sure why tho

[Billfitz]

I just went out to my garage and disconnected the ground lug from my battery. I've got a maintainer attached to the under hood charging posts due to the cold weather, and low and behold, with the battery disconnected there's still power to the car. Comprehend that.

[Haveyouseenjay]

I know this Is a late reply but this actually happened to me today while changing my battery. stupid that some cars don't have rear folding seats.

I used jumping cables from the new battery I had sitting out (or can use another car) to the connections under the hood just the get some power flowing. press the start/stop once (accessory mode) and then press the trunk button. popped open.

*disconnect the jumping cables right after.*

Built: 2013 320i F30

[Mr Podman]

Simply amazing that hooking up a battery to the system would make it work again.

[ronanz]

This is why having "the" master key(s) is sooo important...

.