where do i get one of these breakaway switches i have my plans on how to wire it just need the back piece.http://www.diesel-central.com/photogallery/pictures/Ad_174_2.jpg (http://www.diesel-central.com/photogallery/pictures/Ad_174_2.jpg)hes?

probly any trailer store or maybe napa or tractor supply?

probly any trailer store or maybe napa or tractor supply?

That's what I would suggest. Shouldn't all three have that?

Tractor supply part # 1750242

The funny thing about a breakaway switch (and we didn't appreciate this at first) is that it's built to be normally open. If it disconnects, the contacts close....for the purpose of nailing the trailer brakes full on in the case of a breakaway.

Now, were were thinking that we'd just open one of the circuits in the fuse panel (like Injector A for example) and the motor would die. Not so with a normally open breakaway switch.

So we ended up wiring the breakaway to ground, and connected the other end to the outgo (circuit) side of the fuse. This grounds the circuit and blows the fuse. Works great, stops the motor in its tracks with no chance of relighting it, period. You do have to carry a spare fuse, of course, and know where it goes should this happen on track.

The other way around (using an "open" circuit to kill the injectors) is to use a normally closed 12V relay that opens when energized. Supposedly Ford makes one like this but I don't know the part number or what it comes from. I'm sure you could find one in Newark or other electronics supply house.

Also, pay close attention to your local rules. Some places, they have it explicitly stated that kill devices must also physically shut off the air. Some places, we've had to discuss it a bit with tech so they understood how the electronic version works and were confident that it was safe. Be diplomatic about it. A lot of techs aren't totally up to speed on the newer trucks, and they think mechanical first.

I plan on using this type of switch to trip my air shut off. IMO a fuel kill won't work half as well on a Duramax as a air shut off will.

What good does a fuel shut off do in the event of a runaway? Not a whole lot.

If you make the Injector power wire run through something like this:

killswitch (http://www.mpsracing.com/products/MPS/hc01.asp) you get the same effect.

You can make your own by buying a matched set of two prong connectors. Similar to what they have pictured as the rebuild kit on the above link.

YOu could do it the hill billy way buy about a 25 foot outdoor extension cord, cut the male end of it off about 8", buy a 2" ring, strip back the pigtail on the male end wrap the stripped wires around the ring and connect them(but splice, solder whatever), now use the other end on the circuit you want to interupt. This is a fail safe method. When the ring is pulled the extension cord is disconnected. I ran mine to a 12V automotive relay(these have NC and NO contacts). When the plug is in the relay is energized my fuel pump is on. You could use this to interupt what ever you want. I would suggest a system that requires power to be in the run mode. This is the fail safe method. That is the issue with the breakaway trailer switches.

I have done the "Hillbilly" way on tractors. Works great. I did not use a relay. I set it so the cord was the main power feed to the pump. I like this over the grounded method. I anything goes bad the circuit is cut. With the grounded method if you have connection like corrosion, loose wire, or broken connection and the shutoff is pulled it may not work.:o:

Yeah, I agree with everyone above....I'm not stating I'm a big proponent of the system we have right now. We did what we did at the last minute, and it's the only way I know of to make the breakaway switch pictured above work.

For street pulling classes, most of the organizations don't require a kill anyway so this was more than what was required.

As far as the breakaway not functioning due to corrosion or whatever, then I guess we all better not drive behind people pulling trailers, as this is what everyone is using! The contact closure is kinda wicked with these, so they may be more reliable than you think.

For some reason I don't like having my pump or injector power circuit running all the way back and then back forward again. Seems like it would be prone to glitching open with vibration / potholes or whatever on the street....opens up circuits to potential electrical noise, etc. With the breakway switch, the circuit never knows it's there.

But whatever the approach, I agree with John, it's useless against a turbo seal failure that causes the engine runaway. Later in the season we put one on and stopped using the fuel cutoff. This year I hope to integrate them both and make it a double-whammy.

Matt use the breakaway to power the 12V relay then used the NC contact on the relay. When your switch is pulled it energizes the relay opening the contact. You could still keep your injector power feed wire in the engine compartment. I wouldn't be overly concerned about the noise induced I would think if you keep it close to the frame rail and away from the other stuff it should be relatively noise free. What we do on the 24V is we just open the ignition switch, just like turning off the key. There are a thousand ways to do it, and your method should be fine. Several places that I have been require a demonstration so that would mean you would be popping the fuses. The relay you need is available almost anywhere. It would take care of your popping fuses when it trips. ALso you could still use the ground back there. Just supply the 12V to the relay coil and then use your wire that your grounding the inector power on the other side of the coil.