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kill switch installed

B

Bert

NAXJA Forum User
Location
NY
I just got done installing a kill switch for my fuel pump. Just wanted to share the info on how I did it, but don't ask for pics...that would kind of defeat the purpose of a hidden kill switch if I post pictures of it all over the web.;)

Anyways, I got the info about a ground wire for the fuel pump behind the panel behind the spare tire. I believe it was Mark Hinkley who first posted info about it. Its a 12 gauge black ground wire connected to the fender brace. Anyways, I just cut into the wire and ran wires under some carpet and to a switch I hid somewhere in my jeep (within reach of me from the driver's seat). Its well hidden and mounted snugly. Anyways, i just used a little toggle switch I picked up from Autozone and some 18 gauge wire. Very simple and it puts my mind at ease a little.

I know its not the best kill switch, but it should prevent someone from hotwiring the jeep and driving it off quickly.
 
I wish I had a kill switch for the fawker who cut me off to make an onramp and nearly put my tippy junk on its lid.
Thinking out loud.
 
I am not sure you have such a good design here to interrupt a 12 Ga wire and extend it 10 or 11 feet (to the switch and back) with a pacthed in 18 Ga wire. What is the current capacity of the switch you used? If 12 Ga wire was used in the original circuit, you should have extended it with at least 12 Ga wire and used a switch that can handle 20 Amps continuously.
 
what he said, you will probably toast that switch. probably wouldnt be a bad idea to rewire.
 
actually i checked, the wire and the switch need to be able to accomodate 12volts cause that's what goes through that ground wire, I believe. Both my wire and switch are rated for above 12 volts, so shouldn't it be fine? (i'm asking here) The switch is rated for 20volts continuous. I'm no expert on this, but so far it seems to be fine. I'm going to check the wires and switch to make sure everything looks fine in a few days.

More comments are welcome. It definitely works to kill the pump too, but I'm not going to be testing it very often.
 
Volts and ampres are 2 different things.

The switch must be rated for 20 AMPS.

Remember, it's the amps that'll kill you, not the volts.
 
ok,i checked the switch again. Its a 15 amp switch, sorry for the mistake earlier. So should I get a 20amp switch? or will the 15 amp handle it? Sorry for the dumb questions. I believe the wiring should handle it, but I do have a roll of 12 gauge wire, maybe I'll swap that in. I just happened to have some 18gauge wire opened.

thanks for the help guys.
 
Okie Terry said:
Remember, it's the amps that'll kill you, not the volts.
Click to expand...
it's a combo of both when you grab onto both your bat terminals you are holding what 600 amps in your hands but at only 12v no biggie but if you had a 600amp 220 that you grabbed hold of well let's just say it would be the last time you grabbed anything.
 
i would suggest interupting the wire with a relay, and using the switch to toggle the relay instead...this way you do not interfere with the working of the pump, lengthening the wire even with larger gauge adds resistance reducing the voltage that is being seen at the pump. just my 2 cintz...--chad--
 
Last edited:
bj-666 said:
it's a combo of both when you grab onto both your bat terminals you are holding what 600 amps in your hands but at only 12v no biggie but if you had a 600amp 220 that you grabbed hold of well let's just say it would be the last time you grabbed anything.
Click to expand...
Semantics. Blahhhhh.
 
Bert said:
I just got done installing a kill switch for my fuel pump. Just wanted to share the info on how I did it, but don't ask for pics...that would kind of defeat the purpose of a hidden kill switch if I post pictures of it all over the web.;)
Click to expand...

well now they'll know what to look for when they cant start your shit right away :dunce:
 
im with chad on this you should use a relay .with a long run of wire you will get a drop in voltage . i think the pump is only at 8 volts when running and if it less than that you will lose fuel pressure wich is a bad thing
 
im sorry, im new at wiring and whatnot. why does it matter how long the ground wire is? isnt that energy on its way out anyway?
 
JeepinAudiophile said:
i would suggest interupting the wire with a relay, and using the switch to toggle the relay instead...this way you do not interfere with the working of the pump, lengthening the wire even with larger gauge adds resistance reducing the voltage that is being seen at the pump. just my 2 cintz...--chad--
Click to expand...

thats a great idea, thanks! I'm going to pick up a relay that can accomodate it. thanks for all the comments.
 
small pederson said:
im sorry, im new at wiring and whatnot. why does it matter how long the ground wire is? isnt that energy on its way out anyway?
Click to expand...

Yes it is "on the way out" but it needs to flow in a continous loop. If one end of the loop is choked by a smaller wire, the whole circut will be choked. Not only that, but the smaller wire can heat up because of too much amperage flowing through it. Burning wire + burning carpet = toasted Jeep. This is an extreme circumstance but it's possible.

Voltage will decrease with distance because some energy is always lost to heat. Use a heavier gauge wire for longer runs to avoid this.
 
im using same gauge wire im just wondering why it would matter for the ground if there was a loss of energy over the distance BECAUSE its used energy
 
think of it like a toilet . when you flush you get water in the bowl if the drain was small or a long way off or both it would be not good right.
 
Go to http://www.autospeed.com/cms/A_0059/article.html and read that. Its the anti-theft system I installed into my CJ and its fantastic. You can put the button anywhere and it doesn't matter. As long as the reed switch is hidden you'll be all set.

As for the voltage vs. aperage thing think of it this way. Voltage is static and doesn't move. Amperage is what flows through the wires. Too much aperage and you'll fry the wires.
 
small pederson said:
im sorry, im new at wiring and whatnot. why does it matter how long the ground wire is? isnt that energy on its way out anyway?
Click to expand...

Picture a hose. If you half plug the exit and the hose is full you automatically limit the amount of water that can get in.

My kill switch is wired to my ignition relay. When on the engine will crank and crank, but won't start. Hidden switches are often a pain to use, so hide it in plain site. The wiring for one of my stock switches has been moved to a new switch and the stock switch is the kill switch.
 
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