Can you guys confirm for me if this is the correct and safe way for me to wire in a kill switch to my starter? I see so many variations, some of which include fuses even with the relay. I am REALLY green when it comes to electrical, so appreciate your help. Also, I'm not trying to start a debate or discussion around the merits of kill switches or which systems are wired to kill. Just want to make sure I'd be doing it safely. The Ignition is a GM and I assume if following this diagram I'd be cutting the purple wire coming off the starter? Also, assuming this wiring is right, if I wired in the wire going to my horn to 87a, would that cause the horn to sound upon trying to start the car when the kill switch was open? Posted using the Full Custom H.A.M.B. App!
If someone does not get back to you sooner,I will answer this later. The schemetic I have for this relay is home in the garage that I have to consult. Oldmics
Hi. Assuming that the #85 - 86 terminals are across the relay coil & that the #30 - 87 terminals are the relay contacts that will do it. Jimmie
That will be good. The horn is triggered off a completing to ground. So the 87a prong won't do that. 87a is closed to 30 until the relay is triggered
Wired directly to the horn it would and you could probably crank your car by closing the extra switch and honking horn, LOL. Would'nt recommend that last part though, might be more than the horn relay could handle.
Yeah, gonna claim temporary insanity on that one, correction will not crank motor when honking horn but will honk horn when key turned to start with out extra switch closed.
Pretty sure that's just for the purple wire. At least that's what I get from the S terminal on the starter and reading the post
Not trying to be a smarty pants, but couldn't you just wire an "ON" "OFF" toggle switch to your ignition coil wire. The toggle switch would be hidden under the dash. No relay needed.
Yes I just want to place the relay inline to the purple wire coming off the starter. What capacity relay is needed for that? On the horn, I thought it would be cool to get the horn to blare if someone tried to start the car when the kill switch was open. I don't want to use the coil wire. Posted using the Full Custom H.A.M.B. App!
View attachment 2814698 Turn ignition to start without closing extra switch it's gonna honk the horn, only question would be current capacity of the ignition switch but since OP mentioned a Gm switch it should be fine.
Why not just interrupt the starter switch wire (purple) with a toggle hidden under the dash? If you're worried about theft, it'll take a thief too long to figure it out and he'll leave. Been doing this on my cars forever. Having the horn honk won't help much, it'll annoy the living hell out of everyone in earshot.
24's idea will honk the horn but prolly also fry the ignition switch start position without another relay. Horn's generally take 30+ amps. Another possibility is to get a 30amp double-throw kill switch (or lesser amp cap with another relay) and wire it up like this. Jack E/NJ
That don't really show how it triggers the existing horn relay does it? You'd need to add another horn and relay or redesign the entire existing horn circuit
31V>>>You'd need to add another horn and relay or redesign the entire existing horn circuit>>> I think the horn relay is bypassed and connected directly to the horny hot. Prolly not a good idea without another relay. I agree a separate horn would be simplest. Or maybe disconnect and dedicate one of the two horns to the theft circuit. Leave the other horn alone. I'd like to see the vehicle he's trying to protect. 8^) Jack E/NJ
You'll notice I mentioned that the current capacity of the GM switch would be the only question. Horns do not require a relay to operate IF the switch can handle the load but nothing has been designed that way for decades. I assumed (dangerous I know) that the OP probably had a aftermarket harness using GM components and wiring sizes, generally 12 gauge on the start circuit and 14 gauge to the horn(s). I just went out in the cold to do a little testing on the only GM I could access the wiring easily. Results- 15 amp draw on the start circuit (with a slightly higher spike at first), 4 amp on a single horn. Obviously the best thing the OP could do is check the amperage difference on his own system first.
The horn idea is not a big deal. Just thought it would make some noise (constant on, not intermittent like an alarm). They do make low-amp horns (Hella makes one 115dB that they say draws 5.5 amps). More so I just want a simple switch I can hide to kill the starter. Just something so slow someone down. My understanding was that it would place too much of a load on that toggle switch and that a relay was required. IF that is the case, and the original diagram would work, what capacity relay do I need? Thanks for all the input, guys, i appreciate it.
Best thing you could do is check the amperage draw on the starter circuit and size relay accordingly. If amperage is around 15 amps like the car I checked tonight the normal 20/30 rated relay would be fine but it won't hurt a thing to go to a higher rating. If you do add a low amperage horn to it you will mount it under the front seat right?
Your initial idea wont work. Guys,with all electronics you need to have the schemetic to understand the order. With that said heres the breakdown of the relays terminal assignment 30 = Battery terminal 85 = Ground terminal 86 = Ignition Terminal (Trigger) 87 = Solenoid Terminal (Hot while engaged) 87A = Hot at Rest (Generally not used) So as one can see tieing 85 and 30 together would NOT be a good thing. Its a low amperage relay. I would guess about 10 amps Personally I would go with the flow and install an on off toggle switch on the purple wire and hide it. Hope this helps. Oldmics
Wiring a toggle switch (high quality) happens on every car I wire, simply cut the wire to the solenoid, install a switch, mount it where it's easy to use, never had a toggle fail yet, the one on my 36 is approaching twenty years. The wire to the solenoid doesn't carry big amperage, it merely tells the solenoid (which is a relay) to activate.
The Jalopy Journal
