I have struggled with this for about a week and am getting real tired of it working once and not again, can the switch go bad?? I have moved the ground side of teh batery three times with no sucess. Its a simple two post cut off noting fancy. it also on a 74 dart sport batery in trunk.

Where does the alternator wiring connect? Sounds like somehow the alternator is remaining powered up through a constant or intermittent connection. Battery ground should not be an issue.
Unless the switch is corroded or welded together inside, it should be pretty bulletproof; mine has been on my car for 15 years. When it didn't work, I found the problem was an alternator wire to the starter solenoid, which was enough to basically bypass the cutoff switch. Removing that wire and making sure the alt was only connected to the battery cured the problem. I still owe Mr. P-body a beer, come to think of it...

I have two wire alt. culd the leeds be backwards? it charges fine? I am not exacly sure what wire I am looking for but will go take a peak now and see. I do have a brown wire that is bolted to the back of the alt then two slide on whires to teh back also.

I am real stupid when it comes to wiring and spelling

this is what I have a brown wire comming off my starter going into a relay on the firewall, then there is a brown wire comming off the back of the alt and that goes into the fuse block inside the car. I also have 2 blue wires that goes off the alt into the module on the fender. I dont think the switch is internally welded together because if I kill the car by key and turn the switch off it gets no power when the key is turned back on. could I have a relay problem at the firewall?? I run my msd off the same relay. I am reaching here. I am sure this is very simple to fix I just cant get my hands around this. Again help.

Hmmm. Mine's a 1-wire (GM) alternator. The wire you mention going alt/relay might be the problem, if it's the starter relay; depends on which terminal (power or run).
Basically, the cut-off switch needs to kill the power supply from the battery and the alternator. Seems logical that any "run" functions of the alternator need to be connected to the switch or battery so power is cut off by the switch.
Hang on a bit, and someone here that knows more about this than me will reply.

You need to hook it up so the alt is killed when you turn off the switch. As long as the alt corcuit is hot the engine will run.

dual field alternators will not care which field is wired up to voltage or ground. the main charge wire coming out of the alternator, needs to be on the battery side of the switch, so that when you flip the switch, there is NO source of positive electricity getting to the rest of the system.

I am starting to understand I think. So the brown wire comming off the back of the alternator needs to go back to the switch. You say the battery side of the switch is that the side when the switch is in the off position or is it the side of the switch when in the on position. I know a very stupid question, my thought is if it were to the battery side of the switch I wouldnt need the switch it would always be hot off the battery. Again I only have a two pole switch not a four pole.

it's always hot anyway, it connects to the battery and is what charges the battery when the engine is running.

you want the kill switch to cut off ALL SOURCES OF POSITIVE ELECTRICITY from the car, the only way to do that is to connect the alternator straight to the battery side of the switch.

your switch has 2 points on it. one from the battery, the other goes up to the rest of the electrical system. when the switch is "off" these 2 points are not connected, no power goes through it. when its "on" the 2 terminals are connected inside the switch.

and to answer another dumb question this will not put a draw on the battery because one the key is off and two the switch is off when not running. I got it now and for the last question whay gage wire do I use to go from the battery to the alternator? 10 gage??

stock alternator that puts out around 60 amps? yea, 10 would work, but I'd go at least 8. on my dakota I ran a 4 ga wire from the alternator to the battery, but it was a 120 amp alternator.

You'd have to look at the wire diagrams to verify, because I can't remember off hte top of my head, but the alternator was always wired straight to the battery anyway, it just went through an amp gauge and then to the starter relay before. if you were to ground the charge output wire in stock form, it should throw sparks. I know that on my 98 Dakota, the way it was wired up, the only thing between the battery and the alternator was a 140 amp fuse, so that wire had 12v+ all the time.

lots of little things in your car have 12v+ to them full time, even with the key off.

besides, with a kill switch, turn it off when you park the car, and be sure that NOTHING drains the battery!

Great i will go to the autoparts store this weekend and get some 8 wire in the somewhat same color brown and give this a try. I cant believe its one wire from front to back and its done. This just sounds to simple but simple is good.

OK here we go I talked to my brother and wired my two post switch like his, one problem I had was I did not run the power cable to my starter from the switch I went to the relay then the starter, this could have been one problem. I switched the wires around and its better the engine does not cut as fast as i like but within 4 or 5 seconds. now should it be faster to shut off?? I also still want to take the alt wire back directly to the batery side of the switch instead of going into the the firewall then under the dash. I am assuming it goes back to the fuse block somewhere. I guess the question is how fast should the car turn off?? m i asking for something impossible?? My expectations is I turn the switch to off and it is off as soon as i hear the snap of the toggle in the switch. any more thoughts?? and thanks 70cuda383.

Kiddart

Ya know, security system details probably shouldn't be posted for everyone to see....

this is not a security system its a external cut off switch for tech at the race track. and if someone would like to try and steel my car I would hope they can outrun a bullet. I wont be asking any questions

My mistake.. I like your security system, very effective..

your avitar picture looks very familure where is that car from?? if you want to share. I guy in my neibor hood has a vert just like it. story is he has owned the care from new???

This should answer that..

http://www.moparts.org/moparts/picture/print/pages/Reddig.html

Btw as a test try unplugging one of the field wires at the alternator so it stops charging then flip the switch... If it stops immediately you have a direction..

When everything is wired correctly, and you're not backfeeding anything, it will turn off the same as if you just turned the key. But who knows what 40 year old hack jobs are up under your dash. If you isolate all sources of power, it has to work though! Unless your car runs so hit, it's dieseling!! (if that's the case, it'll run on when you kill it with the key too)

When I turn the key off it shuts off like yesterday no dieseling.