Wiring a Killswitch to coil relay.

Hey everyone!

I'm wiring a fueltech 450 on a snowmobile. I need to wire in a killswitch and a tether on the handlebar. My old killswitch and tether are normally open for stock ignition. You switch it and it grounds out and kills the engine. So on my coil relay the power comes from the box. Along the wire, I want to wire in my tether and Killswitch. If I tie in the kill switch in there. One wire spliced to relay switch wire and one to the negative it just burns the ground wire. Do i need to just have a normally closed switch and don't ground it?

Are you sure your kill switch is normally open? I've wired Pingle kill switches on hillclimb bikes, and those make contact when held up, clip attached, and open when disconnected. I just put it in line with either the power or ground side of the ignition relay trigger.

Most common application where a ground kill is used, that I'm aware of, is with a magneto ignition.

I agree with David, the ground to kill is intrinsically dangerous as any failure of the circuit means the engine cannot be killed, whereas the open kill means the circuit has to be intact to allow the engine to run.

Assuming you have a 12V supply on the snow-mobile, and the actual rules you may need to follow, I'd use a simple 5 pin relay that has both normal open and normal closed (87 and 87a, IIRC) terminals. If you have the ECU power/ignition 'kill' on the 87a terminal it should do what you want.

With the actual kill switch open, the relay isn't powered, and so the ignition will be grounded. Insert the tether to activate the relay and the ignition will not be grounded, fall off or otherwise pull the tether out and the relay will be unpowered and the ignition will be grounded again.

I’m using a normally closed tether in the ignition relay signal circuit. I think a new tether will be the easiest way to accomplish what you’re trying to do. Ps. Small world.

Mitchell that is a small world. Yeah, I got it all figured out now. I ordered a new tether. Yeah, you can't ground it out hahaha. I learned that on my little dummy setup on the bench. Should have known that. Thanks for the responses guys!!!