Quote Originally Posted by rumrumm View Post
Here is a diagram for relays.
Another option is to put the switch on the ground side, between 85 and ground, for even lower current through the switch. Battery power to 30, ignition source (or battery power to both 85 and 30 if you want it available w/o key on, like maybe locks, windows or headlights) to 86, and a low capacity switch on the ground side works good.