[boba8523]

Hi guys,

I'm trying to disconnect the ground negative battery in the trunk of my 2015 m235i. The battery is not stationed on the right hand side of the trunk but rather where flat tires are at.

Anyways, I tried disconnecting the black cable that my finger's pointing at using a 10mm socket, and it created sparks as I was pulling the cable...

To my knowledge, ground isn't supposed to create sparks as it's not "hot", am I getting the correct ground cable?

Can anyone please tell me where the ground cable is?

[RABAUKE]

That looks like the ground cable to me....you'll get sparks on either ground or positive if the other cable is connected.

[///F80M3]

Disconnect the negative terminal from the battery side first.

[WingZeroX5]

That's a negative ground cable bolted to the chassis, so it is a ground

I would brush up on your electricity before working on your vehicle.

[Abax335]

Honestly if you have to ask I woukdnt be working on the car.

But since most people are stubborn and don't take advice yes, but disconnect it off the battery post not at the body unless you are trying to do a draw test

[boba8523]

Thank you all!

[boba8523]

Originally Posted by Abax335

Honestly if you have to ask I woukdnt be working on the car.

But since most people are stubborn and don't take advice yes, but disconnect it off the batter post not there unless you are trying to do a draw test

I've loosened the nut from the terminal clamp enough to the point where the bolt is now moving too when I tighten/loosen...

But the terminal clamp still can't be slid upwards and off. It can rotate left and right though. I've tried "opening" up the clamp but it wouldn't budge either.

Do you know what seems to be the issue?

And how do I tighten the nut now that the bolt is loose too?

[WingZeroX5]

Originally Posted by boba8523

I've loosened the nut from the terminal clamp enough to the point where the bolt is now moving too when I tighten/loosen...

But the terminal clamp still can't be slid upwards and off. It can rotate left and right though. I've tried "opening" up the clamp but it wouldn't budge either.

Do you know what seems to be the issue?

And how do I tighten the nut now that the bolt is loose too?

just keep rotating left and right and add some upward force. It'll come out. If it hasn't been touched since coming out of the factory, it's going to be a bit "sticky"

[boba8523]

Originally Posted by WingZeroX5

just keep rotating left and right and add some upward force. It'll come out. If it hasn't been touched since coming out of the factory, it's going to be a bit "sticky"

It's out!

One question. I loosened the nut too much to the point where the "square-ended" bolt is now loose as well. And basically the nut is stuck on the bolt...

How do I station the square-ended bolt so it doesn't move in order to tighten the nut? It just had to be weird square shaped...

[WingZeroX5]

Originally Posted by boba8523

It's out!

One question. I loosened the nut too much to the point where the "square-ended" bolt is now loose as well. And basically the nut is stuck on the bolt...

How do I station the square-ended bolt so it doesn't move in order to tighten the nut? It just had to be weird square shaped...

Get a pair of pliers and hold it in place while you tighten the nut...

[boba8523]

Originally Posted by WingZeroX5

Get a pair of pliers and hold it in place while you tighten the nut...

Tried that, lost grip... Nut's stuck. Too tight :/

[M3Bimmer77]

Are you sure you wanna keep doing this? I suggest stopping right here and take it to the dealer. Buy a cheaper car to learn on

[WingZeroX5]

Originally Posted by M3Bimmer77

Are you sure you wanna keep doing this? I suggest stopping right here and take it to the dealer. Buy a cheaper car to learn on

This guy made 6 threads on the same subject

Must be a record, 6 hrs trying to disconnect the neg batt terminal

[boba8523]

Originally Posted by M3Bimmer77

Are you sure you wanna keep doing this? I suggest stopping right here and take it to the dealer. Buy a cheaper car to learn on

Would have to first tighten the nut to revert back to original in order to do that.

Any suggestions?

[M3Bimmer77]

I don't know how to help you bc I don't know where you have a problem. It's so straight forward....

The batterry terminal has a square bolt head that locks in the terminal. Just push it in the terminal until it locks then tighten the nut. Make sure the terminal is all the way in. Tap a little bit of needed but don't hit it. Take the car to the dealer to double check.

[Abax335]

You shouldn't have to hold the bolt to tighten it. If you look at the one picture you have the battery clamp itself is squared off so it won't spin. Just push that up with you finger and then try tightening and please please don't over tighten you will snap that bolt.

There is alot of potential damage to control modules you can cause so my advice is please stop working on your car you obviously have no mechanical intuition

[zipphreak]

Stay away from electricity , and working on your car, or learn how to use google.

For DC Power,
Black = Ground
Red = Positive

For Single Phase AC Power,
Black = Hot
White = Neutral
Green = Ground

[Solarphil]

I think everybody should be encouraged to work on their own car. None of us were born with all the knowledge and skills we have now, it took hands-on learning to build the skills. However, I STRONGLY suggest you find a local mentor or trusted wrench that can walk you through the learning stages. Pay them for their time if that's how they earn their living, or reward them with beer and pizza if they do it for fun. Get your hands dirty, ask questions, learn. Don't give up. But do get some help.

[BentZero]

What are you trying to do with your car? :/

[aerostar]

Originally Posted by BentZero

What are you trying to do with your car? :/

The "battery mod" where you play around with all the cables on the battery until your iDrive screen shorts out.

Adds 5 hp

[Boosted_six]

Is this a troll thread?

[BentZero]

Originally Posted by aerostar

The "battery mod" where you play around with all the cables on the battery until your iDrive screen shorts out.

Adds 5 hp

Oh, I thought another M badge on the battery itself did that. Good to know.