Slapstick is considered a lower tier of humor. I would encourage you to leave behind crude jokes such as lighting farts and explore instead the more subtle genres of wit. Find the wry in life.

Hot engineering chicks. Uh huh. Can’t hardly swing a dead cat w/o hitting a hot engineering chick. “Hey babe, why don’t you come over to my pad tonight? We can pull an all-nighter working on heat transfer.”


[quote=“Ranger” post=66347][quote=“turbo329is” post=66345]
Slapstick is considered a lower tier of humor. I would encourage you to leave behind crude jokes such as lighting farts and explore instead the more subtle genres of wit.[/quote]

“I work for Mel Brooks”


At least that’s what I think Slim Pickens says when he punches out a guard to get on the set of a musical. It’s been a while since I saw Blazing Saddles.


Lol, ya, that’s the line. I should rent the movie for our kids. It’s so important to expose children to the classics, don’t you think?

“No, don’t shoot him, it will only make him mad.”


Quick noobie question for those folks with their kill switch location on the passenger side at the harness bar/main hoop junction. This thread has been a great help. I’m wiring the Pegasus 4430 Master Battery Switch with Alternator Protection which is basically the same as the Bimmerworld switch. For those using the resistor, where are you connecting the ground wire to the car body and what gauge wire are you using from resistor to ground?


Another thread revival. :slight_smile:

So a friend and I (he’s finishing up his SE30 car) decided to go the solenoid route for a master switch. Trying to finalize the wiring.

Cutting the main 2/0ga battery cable is a no-brainer. But, this thread seems to insist that the 2 wires running from the positive terminal of the battery have to be disconnected from the battery and each other. This makes sense since the small wire can supply power from the alternator to the DME.

My friend, however, went a different way. Not sure if he found this online, or came to this conclusion based on the troubles he was having trying to cut the OBC out of the wiring harness, but instead of cutting the power to the DME from the alternator, he instead cut the green power running to the DME from the OBC relay box.

It seems to have the intended effect – shutting off the car. Also, it’s a smaller wire that doesn’t need a beefy switch (though it is further away from the rest of the action). I’m planning on running a few remote cutoff switches in the car – one aircraft switch near the driver’s A-piller (probably coming out of the vent, next to a fire pull), one on the center dash next to the other switches, and one large push button switch on the main hoop by the passenger window. I’m considering following his lead.

Just wondering if there’s any fault in the “kill” logic here. It’s hard to determine from the ETM what the green wire does for the ECU. It just says it goes to pin 27. The black wire off the battery junction goes to, effectively, 3 pins marked as “power inputs”. But if cutting power to pin 27 shuts down the ECU and kills the motor, isn’t that sufficient? Any situation where this would fail to kill the engine?

Oh, and here’s a schematic I drew–I mean–uh… conveyed to a 4 year old… who drew it on a computer.

(for me, the GN wire would go to the ignition/run switch, but it would go to the OBC relay in an unmolested car)




Funny story - I just completed something very similar to what you’ve described here.

Pin 27 provides a 12v run signal to the ECU. When you cut that, the ECU essentially thinks you’ve turned off the key.

I wrote a blog post about this with a diagram which hopefully I can provide in a day or so. Here are some pictures of it installed.


Som, it should work. The only drawback I can see is there will still be some current output from the alternator looking for somewhere to go while it winds down. The design of the Bimmerworld-type switches (with alternator protection as mentioned in this thread) will shunt that wind-down current to a resistor. In your setup, the power to the ECU will be cut and the engine will die, but the wind-down alternator current is still momentarily flowing into the rest of your wiring. I don’t think that would cause any problems though.


Cool… think that’s what I’m going to do and just ignore the shunt resistor.

Was trying to think of a way to add a relay to do engage a shunt resistor, but then I thought the time to close the relay would probably be long enough to prevent the desired protection of the shunt resistor.

(plus, adding a relay to this whole deal takes it into the realm of “over complicated” compared to the other, more common approaches)



I like this setup for the simplicity, but I’m concerned about a power spike from the alternator killing something. If I did this setup where would I add the shunt resistor?

I’ve been researching and trying to wrap my head around this whole kill switch thing…


Very few bother with a shunt resister.

We did go thru some work to figure out our kill switch struggles, but at the end of the day it’s not that complicated. You’ve got 2 wires that HAVE TO REMAIN SEPARATE and both must both be interrupted by the kill switch. One is the wire from batt to alternator, and the other is the power wire to the DME. Both can be easily ID’d because they run from batt to power lug at the firewall in front of the passenger.

In my case the wires are separate from engine compartment to kill switch, but then I have only one wire from switch to batt.



Do you have a link to your blog post?

Thank you


Check your inbox, I can send you my writeup.

Working on getting it back online now for others in the future…


I was able to get the link back up. Please let me know how I can improve the article as I’m sure others will have similar questions.

Electron Speed E30 Kill Switch


Thanks! I’ve got the parts and will try to wire this up pretty soon.