Electrical Cut-off/Alternator Help

#1

I just spent a very long (and enjoyable) lunch hour visiting my "baby" at Chris Schimmel’s shop, Competition Cages. He’s doing more than just installing my cage, and one item Chris is helping with is the 4-terminal electrical cut-off installation. He and I could not determine where the excitor wire on the alternator is that we need to interupt so that the engine will be killed if it’s running and the switch is turned to off. Alternatively if there’s another place to interupt this lead, say in a wire harness under the dash, that would be helpful. What have y’all done?

Thanks,
Sasha

#2

Sasha,

I’m pretty sure that one side of mine shorts the ignition coil to ground at the front battery block… I’ll take a look at it tonight and shoot you and Chris an email.

BTW, Chris did a great job with my cage, I’m sure you’re going to be very happy with yours.

#3

All the connection for my kill switch are at a distribustion block in the engine bay, on the passenger side. The A/C lines run right next to this area. The battery line connects to a plastic post that is bolted down to the firewall (once again, accessible under the hood). Your alternator also connects to this area with a smaller gauge wire. You can trace the wire all the way to the alternator to verify. This is actually an ideal spot for BMW to put the connection as it allows relatively easy install of a kill switch (you don’t have to cut any factory wiring.)

I hope this helps! - wish I had pics on hand…

-Vic
SO #325

#4

I was just looking into this yesterday and still have questions.
Attached is part of a wiring diagram from the 1989 ETK. The alternator is in the lower right. Do you interrupt the wire that goes from the Battery Junction Block to the starter and alternator (approx 4 or 6 gauge wire) or the one labelled 1.5BU (about 14 ga) that goes up to C101?

Brain has some good pics of a nice kill switch setup in the Gallery here (car 105)

cheers,
bruce

Post edited by: leggwork, at: 2006/01/19 15:20

#5

here is the wiring diagram …

Post edited by: leggwork, at: 2006/01/19 15:29

#6

one more try (had to try this a couple of times as I discovered the file size limitations…)

save the file and eliminate the .txt extension [file name=alternator_wiring.gif.txt size=35389]http://spece30.com/media/kunena/attachments/legacy/files/alternator_wiring.gif.txt[/file]

Post edited by: leggwork, at: 2006/01/20 00:42

#7

I interrupted both wires at the battery junction block (one for battery, one for starter).
-Vic

#8

but what about the smaller gauge wire that is supposed to go to the alternator?
The wire to the starter is a 4 to 6 ga wire.
thanks,
bruce

victorhall wrote:

[quote]I interrupted both wires at the battery junction block (one for battery, one for starter).
-Vic[/quote]

#9

The battery wire is big big gauge, and the other (for the alternator) is indeed smaller. I hope I didn’t give the impression that both wires are big. The kill switch I have matches this configuration as it has one BIG terminal for the battery, and then spade terminals on the bottom for the smaller alternator wire.
I can probably get some pics this weekend if you need.
-Vic

#10

I’m just confused because the wiring diagram only shows big gauge wires coming off the battery junction point - I need to get off the computer and go look at the car!
cheers,
bruce