Moparts
Cut Off Switch UPDATE!!!! AGAIN UPDATE!!!!!!!!
Posted By: Kiddart
Cut Off Switch UPDATE!!!! AGAIN UPDATE!!!!!!!! - 05/25/11 01:45 AM
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.
Posted By: topside
Re: Cut Off Switch - 05/25/11 01:54 AM
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...
Posted By: Kiddart
Re: Cut Off Switch - 05/25/11 02:00 AM
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
Posted By: Kiddart
Re: Cut Off Switch - 05/25/11 02:55 AM
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.
Posted By: topside
Re: Cut Off Switch - 05/25/11 03:50 AM
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.
Posted By: stumpy
Re: Cut Off Switch - 05/25/11 03:52 AM
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.
Posted By: 70Cuda383
Re: Cut Off Switch - 05/25/11 12:38 PM
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.
Posted By: Kiddart
Re: Cut Off Switch - 05/25/11 05:31 PM
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.
Posted By: 70Cuda383
Re: Cut Off Switch - 05/25/11 06:56 PM
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.
Posted By: Kiddart
Re: Cut Off Switch - 05/25/11 09:03 PM
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??
Posted By: 70Cuda383
Re: Cut Off Switch - 05/25/11 11:14 PM
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!
Posted By: Kiddart
Re: Cut Off Switch UPDATE!!!! - 05/26/11 01:29 AM
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.
Posted By: Kiddart
Re: Cut Off Switch UPDATE!!!! - 05/27/11 02:45 AM
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
Posted By: 1_WILD_RT
Re: Cut Off Switch UPDATE!!!! - 05/27/11 02:48 AM
Ya know, security system details probably shouldn't be posted for everyone to see....
Posted By: Kiddart
Re: Cut Off Switch UPDATE!!!! - 05/27/11 02:54 AM
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
Posted By: 1_WILD_RT
Re: Cut Off Switch UPDATE!!!! - 05/27/11 03:02 AM
My mistake..
I like your security system, very effective..
Posted By: Kiddart
Re: Cut Off Switch UPDATE!!!! - 05/27/11 03:08 AM
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???
Posted By: 1_WILD_RT
Re: Cut Off Switch UPDATE!!!! - 05/27/11 03:17 AM
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..
Posted By: 70Cuda383
Re: Cut Off Switch UPDATE!!!! - 05/27/11 04:27 AM
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)
Posted By: Kiddart
Re: Cut Off Switch UPDATE!!!! - 05/27/11 05:26 PM
When I turn the key off it shuts off like yesterday no dieseling.
Posted By: 1_WILD_RT
Re: Cut Off Switch UPDATE!!!! - 05/27/11 05:35 PM
Is this with the alternator unplugged? If so something in the wiring is acting like a capacitor, storing energy which takes a few seconds to be depleted when you shut the key off..
Posted By: sshemi
Re: Cut Off Switch UPDATE!!!! - 05/27/11 07:21 PM
do you have an electric fuel pump?
I guess you do and when you flip the switch you kill the pump and it runs out of fuel.
All problems will be solved if you connect the killswitch to the negative side.
I know the rulebook says to cut the + side but any track guy with a commons sence do realize that it is the best way to do it.
Posted By: Kiddart
Re: Cut Off Switch UPDATE!!!! - 05/28/11 02:47 PM
I have secured some 8awg wire and will work on this today. Since we are still getting rain and it's crappy in detroit I dont see a problem having this sorted out today. I will report back later today on status or for more help.
Raul I may call you later and take you up on your offer.
Posted By: 70Cuda383
Re: Cut Off Switch UPDATE!!!! - 05/28/11 02:55 PM
with a carb, when you cut the fuel pump off, it's got enough fuel in the bowls to idle for another 2-3 minutes. track guys probably won't like that too much, and wouldn't pass tech.
Posted By: sshemi
Re: Cut Off Switch UPDATE!!!! - 05/28/11 07:05 PM
yeah.. maybe a stock 318 will but not a racemotor.
I said any track guy with some cerials in the box will let it pass if you cut the neg.
Posted By: Just-a-dart
Re: Cut Off Switch UPDATE!!!! - 05/28/11 07:13 PM
Kiddart you are not alone with this problem a lot of people have trouble with this. 70cuda383 is giving you good info I just have a few things to add. When you run that new wire from the Alt. output to the battery side of the disco switch remember it will be Hot all the time,switch on or off. Route it so it's protected. Also remember to insulate or remove old wire to Alt. output. Have fun.
Posted By: 70Cuda383
Re: Cut Off Switch UPDATE!!!! - 05/28/11 08:46 PM
Quote:
yeah.. maybe a stock 318 will but not a racemotor.
I said any track guy with some cerials in the box will let it pass if you cut the neg.
must be one serious race motor! my 383 stroker that was making 535 lbs of torque would idle for several minutes once you cut off fuel. probably an honest 2-3 minutes.
why take the chance of a tech guy passing it when it isn't technically legal? the idea behind the kill switch, is that when you crash and the safety crew comes up behind your smoldering mess of what used to be a car, so they can rescue you, they want everything off for their own safety. kind of like a "lock out, tag out" type situation, so they want to kill battery power to everything, and they want the motor to stop spinning.
if Kiddart's got it wired now so that it runs for 2-3 seconds before dying, that would be better than cutting power to an electric fuel pump and letting the motor idle the bowls empty in 2-3 minutes.
I'm gonna guess that this is a street car and not an all out, massive hp motor. it might even be a "street 318" 
and yea...insulate EVERYTHING! use thick insulated wire to feed the power to the car up through the starter, and a thick insulated wire coming off the alternator. 1/2 or 5/8 heater hose makes for great wire insulation when you have to feed it around sharp edges or tight bends.
Posted By: Kiddart
Re: Cut Off Switch UPDATE!!!! - 05/29/11 02:19 AM
For Startes its a Street Strip car that is barley leagal on the street. it was a 318 from the factory, Good guess.
Big update!!!
It took way longer than I ever expected I ran a temp wire from the alt to the positive side of the switch while disconnecting the original, the car would not start?? So I reconnected the original wire and oh for havens sake the car started.
With that comment said, I commenced to tracing the cut/hacked wire in thru the dash up around, down and over to its connection point, the light switch??? I have no idea if that was the original point of contact of the wire. After pulling half the dash and the dropping the column I was able to remove the wire from its point of origin. Now in the mean time I have every Tom, Dick and Harry coming over to see what’s wrong or what I am changing.
The wire that was in the car was cut and spliced 8 times, I still retain it if someone would like to see it. So I take the new wire run it in its final spot and go to start the car……….. Nothing!!!!! AHHHHHHHH!!!!!!
I am now ready to jump off my roof, I stop take a break and found that I didn’t put the wires back on the headlight switch the same way they came off?? Not sure what that was about. So after 5 hours of swearing and pulling miles of electrical tape off I now have a functioning cut off switch. And when you hit the switch the car stops as I expect it to, YESTERDAY!!! Very happy with the results.
Thanks for all the help and if any good came out of this my wife suggested I rewire the car with all brand new stuff. She feels it would better protect our investment.
God I just love my wife
Thanks fellas for all the guidance.
Kiddart
Posted By: 70Cuda383
Re: Cut Off Switch UPDATE!!!! - 05/29/11 04:03 PM
With 40 years of previous hacks and splices, your wife is a smart chica! You can do it the fast, easy, but expensive way--buy all new re-man'd harnesses at 1-2 grand. Or you can make them yourself. It's very easy to do, but will take some time. It'd be cheap too.
At least you got the kill switch working correctly!!
Posted By: sshemi
Re: Cut Off Switch UPDATE!!!! - 05/29/11 06:18 PM
Quote:
Quote:
yeah.. maybe a stock 318 will but not a racemotor.
I said any track guy with some cerials in the box will let it pass if you cut the neg.
must be one serious race motor! my 383 stroker that was making 535 lbs of torque would idle for several minutes once you cut off fuel. probably an honest 2-3 minutes.
why take the chance of a tech guy passing it when it isn't technically legal? the idea behind the kill switch, is that when you crash and the safety crew comes up behind your smoldering mess of what used to be a car, so they can rescue you, they want everything off for their own safety. kind of like a "lock out, tag out" type situation, so they want to kill battery power to everything, and they want the motor to stop spinning.
if Kiddart's got it wired now so that it runs for 2-3 seconds before dying, that would be better than cutting power to an electric fuel pump and letting the motor idle the bowls empty in 2-3 minutes.
I'm gonna guess that this is a street car and not an all out, massive hp motor. it might even be a "street 318"
and yea...insulate EVERYTHING! use thick insulated wire to feed the power to the car up through the starter, and a thick insulated wire coming off the alternator. 1/2 or 5/8 heater hose makes for great wire insulation when you have to feed it around sharp edges or tight bends.
I see your point here and i am not arguing with that its just that if you were allowed to cut the neg side ,there wouldnt be ANY problems.
Its just as safe, if not even safer, to cut the - side.
just a weird nhra rule.
Posted By: Kiddart
Re: Cut Off Switch UPDATE!!!! - 05/30/11 12:46 AM
70cuda383 not only is she smart she is hot too!!!
Posted By: 68-scatpack-rt
Re: Cut Off Switch UPDATE!!!! - 05/30/11 03:14 AM
Quote:
Quote:
Quote:
yeah.. maybe a stock 318 will but not a racemotor.
I said any track guy with some cerials in the box will let it pass if you cut the neg.
must be one serious race motor! my 383 stroker that was making 535 lbs of torque would idle for several minutes once you cut off fuel. probably an honest 2-3 minutes.
why take the chance of a tech guy passing it when it isn't technically legal? the idea behind the kill switch, is that when you crash and the safety crew comes up behind your smoldering mess of what used to be a car, so they can rescue you, they want everything off for their own safety. kind of like a "lock out, tag out" type situation, so they want to kill battery power to everything, and they want the motor to stop spinning.
if Kiddart's got it wired now so that it runs for 2-3 seconds before dying, that would be better than cutting power to an electric fuel pump and letting the motor idle the bowls empty in 2-3 minutes.
I'm gonna guess that this is a street car and not an all out, massive hp motor. it might even be a "street 318"
and yea...insulate EVERYTHING! use thick insulated wire to feed the power to the car up through the starter, and a thick insulated wire coming off the alternator. 1/2 or 5/8 heater hose makes for great wire insulation when you have to feed it around sharp edges or tight bends.
I see your point here and i am not arguing with that its just that if you were allowed to cut the neg side ,there wouldnt be ANY problems.
Its just as safe, if not even safer, to cut the - side.
just a weird nhra rule.
breaking the negative battery cable will not stop the car from running. the alternator will still be providing power to the fuse block. same thing as just intercepting the positive cable. you need to "kill" the alternator and the battery to de-energize the electrical system. 
Posted By: sshemi
Re: Cut Off Switch UPDATE!!!! - 05/30/11 04:09 PM
Quote:
Quote:
Quote:
Quote:
yeah.. maybe a stock 318 will but not a racemotor.
I said any track guy with some cerials in the box will let it pass if you cut the neg.
must be one serious race motor! my 383 stroker that was making 535 lbs of torque would idle for several minutes once you cut off fuel. probably an honest 2-3 minutes.
why take the chance of a tech guy passing it when it isn't technically legal? the idea behind the kill switch, is that when you crash and the safety crew comes up behind your smoldering mess of what used to be a car, so they can rescue you, they want everything off for their own safety. kind of like a "lock out, tag out" type situation, so they want to kill battery power to everything, and they want the motor to stop spinning.
if Kiddart's got it wired now so that it runs for 2-3 seconds before dying, that would be better than cutting power to an electric fuel pump and letting the motor idle the bowls empty in 2-3 minutes.
I'm gonna guess that this is a street car and not an all out, massive hp motor. it might even be a "street 318"
and yea...insulate EVERYTHING! use thick insulated wire to feed the power to the car up through the starter, and a thick insulated wire coming off the alternator. 1/2 or 5/8 heater hose makes for great wire insulation when you have to feed it around sharp edges or tight bends.
I see your point here and i am not arguing with that its just that if you were allowed to cut the neg side ,there wouldnt be ANY problems.
Its just as safe, if not even safer, to cut the - side.
just a weird nhra rule.
breaking the negative battery cable will not stop the car from running. the alternator will still be providing power to the fuse block. same thing as just intercepting the positive cable. you need to "kill" the alternator and the battery to de-energize the electrical system.
wrong. no negative means no circuit
Posted By: Just-a-dart
Re: Cut Off Switch UPDATE!!!! - 05/30/11 06:50 PM
SShemi that would be true if it was running off the battery and had no altenator. The proplem he was having was the alt. powering the ignition. The neg. side of alt. is connected internally in the altenator disconnecting the battery neg. will not shut it down. Also the rules want the disco switch in the pos+ side of the circuit.
Kiddart in the future you might want to post ? like this on the race forum.
Posted By: Blown71X
Re: Cut Off Switch UPDATE!!!! - 05/30/11 07:29 PM
Quote:
wrong. no negative means no circuit
Wrong ! that just means you have taken the battery out of the equation..The Alternator is still active.
Go out and pop either cable off of your daily driver with it running and get back to me, tell me what happens 
Posted By: sshemi
Re: Cut Off Switch UPDATE!!!! - 05/30/11 08:00 PM
ok so it is me thats got this wrong. i forgot that it is a ac alt witch stays magnetized ones turned on.