Battery Cut Off Switches

[rogbmw]

With the cold weather lingering on the east coast, there has been much talk about battery cut off switches. Most do not realize that when BMW shipped the 8 series to the US it had factory installed cut off switches for the battery. My 850 CSi was a BMW NA car for a period of time when it was new, and they did not remove the cut off switches. It was told to me by a friend who was the service manager at a BMW Dealership during the time the 8 was brought in said it was part of the pre-delivery checklist to remove the switches and send them back to BMW. Evidently the 8 was not the only BMW that had this switch. He said they used to send boxes of them back. Here is a picture of my switches which were never removed.

[GimmieSumMo72]

thats cool... any part # for them?

[LouM]

link: http://www.discountmarinesupplies.co...CT_SWITCH.html

[Ladislav]

link: http://www.discountmarinesupplies.co...CT_SWITCH.html

Harbor Freight has the same exact ones.

[Jenya]

Off topic: is that the right way to position the floor jack inside of the compartment? I have been putting it the other way around in there haha (which worked well).

[MParallel]

Funny you post this now.

I got mine 2 days ago, as one was up on Ebay.com last month. I have been looking for one for 3 years since I first saw a post about it.

The option is listed as

S818A MAIN BATTERY SWITCH |Battery master switch 900A APPR. VEH.IMMOBILIZAT. ACC. TO AZT/TUEV Electronic immobilizer.

Many people se this on their list, but can't find it. As you said, they were taken out, but I guess a handfull of them got left.

Here's mine



Supposedly there is some piece that goes over the "contra" terminal on this cable where it connects to the negative lead you take off the battery and attach to his.

Can you confirm this?

GimmieSumMo72: There is no part#. I have checked the ETK for ages. The theory that BMW took them out supports this. It's not an item you can buy.

Of course any automotive shop will sell one of these switches (without the cable though) but as an OEM fetishist, it's nice to have the original BMW dealer used version.

These are the only pictures I have ever seen of it (and he one in this topic now) and were the pics that made me aware of this part. They were posted in december 2006 in the Show Me Your Rare Parts thread:

(e36)






As you can see, and from the O/P, the fact that is just lies around the battery and is not bolted to a panel, only confirms the theory more that they were to be taken out at delivery.

PS: switch is made by Hella.

[Ladislav]

PS: switch is made by Hella.

Must be a shameless Chinese copy - look the same, but I never had them side-to-side.

[rogbmw]

Jenya - I don't think my jack has ever been out of the car, but I don't know if it is the correct way or not.

MParallel - I am not sure if my switch has the silver barrel at the end or not. I'll try to check the weekend.

[MParallel]

Must be a shameless Chinese copy - look the same, but I never had them side-to-side.

What's a shameless copy?

You do know Hella don't you?

MParallel - I am not sure if my switch has the silver barrel at the end or not. I'll try to check the weekend.

It will. It's the new "negative" terminal, as the other side (the clamp) of the killswitch will go onto the battery's negative terminal.

[Winks]

With the cold weather lingering on the east coast, there has been much talk about battery cut off switches. Most do not realize that when BMW shipped the 8 series to the US it had factory installed cut off switches for the battery. My 850 CSi was a BMW NA car for a period of time when it was new, and they did not remove the cut off switches. It was told to me by a friend who was the service manager at a BMW Dealership during the time the 8 was brought in said it was part of the pre-delivery checklist to remove the switches and send them back to BMW. Evidently the 8 was not the only BMW that had this switch. He said they used to send boxes of them back. Here is a picture of my switches which were never removed.

I know its time to bring this one back but has anyone figured out the part number for this item or where I could find a set.

[TxGR8White]

I know its time to bring this one back but has anyone figured out the part number for this item or where I could find a set.

well, if you would read through all the threads in this post, you will see that there is NO part number - why???, because they were never meant for public consumption.

[bobn8er]

Whichever cut off switch you use, there are several on the market and are universal for all cars and available at numerous auto retail stores, make sure to tender the battery ocassionally with a charger otherwise you will be replacing the battery anyway come spring time.

[TxGR8White]

Whichever cut off switch you use, there are several on the market and are universal for all cars and available at numerous auto retail stores, make sure to tender the battery ocassionally with a charger otherwise you will be replacing the battery anyway come spring time.

...batteries (plural)..

[bobn8er]

...batteries (plural)..

Thanks for the clarification

[rogbmw]

The "splice" where the cut-off switch mated up with the battery negative wire was simply wrapped with foam, then secured with zip-ties. As I originally stated, they were meant for transportation purposes, then to be removed.

[mjrgroup]

I have a cut-off switch just like in your pic, but just one switch for both batteries. It works great whenever I need to do electrical work on the car. Can't imagine not having one.

You can see part of the switch on the left side:

[CANDOO]

I got the one I used in my 944 at WalMart for $13.

[Winks]

Here is what I was considering buying one of those hella marine switches like this (http://www.hellamarine.com/?a=3&t=3&...ID=212&pcid=37) disconnecting the negative ground bolt on the left hand side of the trunk, taking the two negative battery cables (one for each battery) and connecting to one side of the switch and running a new single negative cable from the other post of the switch back to the negative post on the car.

My Question is that since I have 2 1000 CCA batteries in the trunk is it better to run one switch per battery or will one switch total be fine? There is also the option of running a switch like (http://www.hellamarine.com/?a=3&t=3&...ID=213&pcid=37) though it may be overkill.

well, if you would read through all the threads in this post, you will see that there is NO part number - why???, because they were never meant for public consumption.

I have read the post but I was hoping for one of two things to be discovered; first that their is a bmw part number that has slipped through the cracks, or a part identification number that I could use to try and track one down (always good to be optimistic), or secondly their is an aftermarket company that is producing a e31 specific switch.

[hhy2k]

My battery cut off switch:

[Winks]

My battery cut off switch:

You don't store yours in winter? I am just sick of a dead battery. I have a problem with my general module and if the car sits for more then 2 days the batteries are shot. I am waiting for winter before I pull out the module and have it repaired. That way the car can be enjoyed up until her winter hibernation. It would be nice to have a quick battery disconnect to use now.

[8eights]

2 day battery drainage for me meant not enough battery, A new upgraded set will fix your issue.

[Winks]

I just put in two 1000A interstates, they were the largest batteries I could find and still have the problem. A few fellow members indicated that my problem was the general module. When she goes for her winter sleep I will pull out the GM and see if I can get it tested and repaired. The car does not get run in bad weather so it would be nice to switch off the batteries when not in use.

[IcemanBHE]

Try unplugging the phone module....if you have one.

[Winks]

Try unplugging the phone module....if you have one.

No the car has the phone delete option.

[bandittwo2]

i have a 740 from canada which might have this switch on it. im going to check today..