anyone here wire one of these? moroso tells me to wire alt. wire to starter side of switch. which alt. wire goes to the switch, field wire or battery wire?

Battery wire from post terminal on alternator gets routed to the switch location so when you hit the switch it actually shuts the car down. I'm sure someone will post the mad-electrical page. you'd be surprised at how many folks think that since the switch is off and nothing will get power to start the car that the switch is doing its job, but never have the car running and flip the switch to test it. Island Dragway and Epping tech have both randomly asked to start the car to make sure the switch is doing its job to also shut the cars electrical system down.

ok, what do i do with the battery wire on the alternator now if i'm running a new wire to the switch? i believe this wire currenly runs to the starter relay.

If this is a rear mounted switch it is not legal to wire it the way you have it posted as it will not shut the power off it the engine is running. The alternator wire has to go to the battery side of the switch not the starter side so that when the switch is in the off position alternator power is also cut.
If you wire it to the starter side the engine will keep running on alternator charge. The engine will not start with the switch wired in this way but once running it will keep running even with the switch off.

ok, thanks guys. the car will be raced and has battery in trunk. i thought it would work both ways, but now i see it has to go on battery side of switch to be track legal.

does the alternator wire to the switch need a in line fuse and how big? thanks

Do yourself a favor and put a relay in that kills the alt wire from the battery to alt.

It's great to have a car with a cutoff switch that still burns to the ground because the alt wire is hot and the source of the fire. Flipping the switch to kill power does no good.

This is the way I do mine. Once you flip the switch, NOTHING is hot beyond the trunk.


Here are a few others:

This one is the same as the above except the extra relay for the alt wire.


Very basic, but, legal


Alt relay example