I use the enertia switch out of a 2000 and up Ford. the junkyards are full of them, just look in the trunk.
Enertia switches must be wired into the control side of the relay. They are not rated to handle pump current.
So, for those of us who aren't that smart with wiring, would that be the lighter gauge switched power wire? Is it wired by just cutting the relay wire, and wiring it one side in, one out?