Relay Wiring for Dummies like me - The 1947 - Present Chevrolet & GMC Truck Message Board Network

cst350 · 05-14-2014, 12:52 PM

Ok, I want to wire a kill switch to my distributor. I want to use a small switch so I need to use a relay. I go online to search for relay wiring and I get so many options I don't know which one will work. I need to know what numbers should go to:

Wire from ignition (That I will cut)
Wire going to distributor (other end of wire I will cut)
Power for the relay (12 volt from fuse block)
Ground (putting kill switch from here to chassis ground)

I think it goes as follows:

86-Wire from ignition (That I will cut)
87-Wire going to distributor (other end of wire I will cut)
30-Power for the relay (12 volt from fuse block)
85-Ground (putting kill switch from here to chassis ground)

Also, should my 12 volt from fuse block be a certain fuse size? Do I go for 12 volt constant, ignition or Accessory?

Any help or comments appreciated!!!

Andy4639 · 05-15-2014, 12:08 AM

I would use a 20amp fuse in it.

71swb4x4 · 05-15-2014, 12:23 AM

Why do you need a relay? It's just a 12 volt circuit, just put the switch in there.
I am not an electrical expert, so if you need the relay, tell me why so I can learn something.

cst350 · 05-15-2014, 09:52 AM

Andy4639... thanks, that schematic was one of the ones I found too. The valet switch made me confused though because I want a ground interupt ( I think?)

71swb4x4... from what I have read some switches cant take the full power. The switch I am using is very small so I can hide it.

Andy4639 · 05-15-2014, 10:14 PM

Just leave it out of the picture then. Wire it straight out.

The distributor will pull a bunch of amps through it so the switch most likely want handle it. The relay should be good for 30-40amps at least. Plus it makes the wiring system less over loaded to.

67 Burb · 05-19-2014, 01:32 PM

Here's the way I would do it. It is the simplest way to do what you want. Just cut the wire from the ignition switch to the distributor. Add the relay between the two ends like in the diagram and your small hidden switch in the ground wire. When the hidden switch is left closed, all will work as usual and when you want the anti-theft, open the hidden switch. Done.

05-14-2014, 12:52 PM	#1
cst350 Registered User Join Date: Dec 2003 Location: nor cal Posts: 219	Relay Wiring for Dummies like me Ok, I want to wire a kill switch to my distributor. I want to use a small switch so I need to use a relay. I go online to search for relay wiring and I get so many options I don't know which one will work. I need to know what numbers should go to: Wire from ignition (That I will cut) Wire going to distributor (other end of wire I will cut) Power for the relay (12 volt from fuse block) Ground (putting kill switch from here to chassis ground) I think it goes as follows: 86-Wire from ignition (That I will cut) 87-Wire going to distributor (other end of wire I will cut) 30-Power for the relay (12 volt from fuse block) 85-Ground (putting kill switch from here to chassis ground) Also, should my 12 volt from fuse block be a certain fuse size? Do I go for 12 volt constant, ignition or Accessory? Any help or comments appreciated!!!

05-15-2014, 12:08 AM	#2
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,945	Re: Relay Wiring for Dummies like me I would use a 20amp fuse in it. __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.

05-15-2014, 12:23 AM	#3
71swb4x4 Senior Member Join Date: Nov 2003 Location: Brookings, SD Posts: 10,497	Re: Relay Wiring for Dummies like me Why do you need a relay? It's just a 12 volt circuit, just put the switch in there. I am not an electrical expert, so if you need the relay, tell me why so I can learn something. __________________ Some people are like slinkies, they aren't good for anything, but you can't help but smile when you see one tumble down the stairs.

05-15-2014, 09:52 AM	#4
cst350 Registered User Join Date: Dec 2003 Location: nor cal Posts: 219	Re: Relay Wiring for Dummies like me Andy4639... thanks, that schematic was one of the ones I found too. The valet switch made me confused though because I want a ground interupt ( I think?) 71swb4x4... from what I have read some switches cant take the full power. The switch I am using is very small so I can hide it.

05-15-2014, 10:14 PM	#5
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,945	Re: Relay Wiring for Dummies like me Just leave it out of the picture then. Wire it straight out. The distributor will pull a bunch of amps through it so the switch most likely want handle it. The relay should be good for 30-40amps at least. Plus it makes the wiring system less over loaded to. __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.

05-19-2014, 01:32 PM	#6
67 Burb Registered User Join Date: Dec 2011 Location: Brandon, Manitoba, Canada Posts: 548	Re: Relay Wiring for Dummies like me Here's the way I would do it. It is the simplest way to do what you want. Just cut the wire from the ignition switch to the distributor. Add the relay between the two ends like in the diagram and your small hidden switch in the ground wire. When the hidden switch is left closed, all will work as usual and when you want the anti-theft, open the hidden switch. Done. Attached Images __________________ Bob 1967 2wd Burb, 350/TH350, 3.73 posi



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