BMW Factory Kill Switches (They exist)

Markos

Markos

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Well you won't find the part numbers on realoem, but BMW did make battery disconnect switches. They came in two flavors: rocker switch and magnetic switch. I own one of each, and have the part numbers as seen below. I dug them out of storage today and snapped a few pics. I'll reply later with the back story on these switches. they include a trickle wire that allows a tiny bit of current to pass through to support the clock and radio presets from resetting.

I thought you all might find this interesting! I googled a part number and found at least one potential seller in the motherland.

I didn't take a pick, but they have a small BMW connector to disconnect the cord and route through the firewall. I can take more pics if anyone is interested. The rocker switch itself has a unique part number also.

Magnet activated:
21569747282_1f4c9c3989_b.jpg

20958264494_e252641f18_b.jpg


Rocker activated:
20958260204_5c6baf6c62_b.jpg
 
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Very cool. And here I was thinking I was slick because I wanted to wire the fog light switch as an ignition cut.
 
deQuincey said:
what is the principle of the magnetic one ?

how does it work ? do you need to place a magnet to operate it ?
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You run a magnet over the red light with an off-to-on, or on-to-off swipe.

The part number on the back of the brass terminal is: 61 31-6 929 777 - 01. The part number on the back of the magnetic switch is:
61 31-6 935 706. I'll need to snap a pic of the back of the toggle.

I'm not sure if these were for sale. I was told that they were used for transporting the cars without draining the battery, then the dealer would throw them away. That doesn't make total sense though, given that BMW made one with a magnetic switch.
 
The date stamp on one of them seems to indicate 11/06, the other one 01? Surely not early 70's, that trickle wire came later.
 
HB Chris said:
The date stamp on one of them seems to indicate 11/06, the other one 01? Surely not early 70's, that trickle wire came later.
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Sorry I never specified. These are from mid 2000's cars. Supposedly BMW stopped using them around that time also.
 
Presuming you are thinking about this as an anti-theft measure...I am thinking about a stealth fuel pump power cut off.

MyFemurHurts said:
Very cool. And here I was thinking I was slick because I wanted to wire the fog light switch as an ignition cut.
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Ohmess said:
Presuming you are thinking about this as an anti-theft measure...I am thinking about a stealth fuel pump power cut off.
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I am a big fan of fuel pump cutoff switches. The experience of a failing pump is a little less intuitive compared for thieves IMO. The other thing is that the car will run for about 10 seconds, which may be enough time for the car to move. Therefore, the attempted theft may be more visible to you or authorities. I've had a fuel pump cutoff on my jeep for 10 years. It is a simple hi amp switch that interrupts the ground.

My E9 has a mechanical fuel pump. You can use the BMW switch to cutoff the battery or the starter. I like the starter idea but one could always pop the clutch...
 
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I have a mechanical fuel pump now, but it needs to be removed to make room for the three webers. I plan to install a relay that will cut power to the pump if the engine is not running, and it would be a simple thing to wire a switch into the signal path for the wire that the relay uses to sense whether the engine is running.
 
I'd prefer to run a fuel pump cut, but I'm still running the mechanical pump like you guys.

I do have a funny feeling if someone was going to steal my Coupe the stick shift and cold start would deter them anyway.
 
Stevehose said:
Except you have to open the hood to engage it. With an ignition swith you can flip it on as you exit the car.
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Exactly what I was thinking. Put then my log light switch broke the first time I pressed it, so that idea went by the wayside as well.
 
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