when i hooked some lights w/a switch in a car i just ran a wire from the positive term. of the battery to the switch (dont use those stupid led ones, i had one once and it was nothing but trouble and eventually broke) then i ran all the lights in a series and grounded them properly. the way i have it in my car though is without a switch, i just grounded the lights and ran the power wire to the parking light furse(so when i turn on my lights, the leds come on) that way there isnt an ugly switch to deal with.