not sure what your after but here is some info,
if your checking the circuit for a break or short take an ohm meter and probe from the headlight switch spider to the bulb contact. the ohm meter should read almost no resistance close to the same as if you just touch the test leads together. if you are showing high resistance you can locate the problem by testing the circuit in different areas.
if you want to see if your getting power to the headlights or tailites just activate that circuit and use a 12 volt test light. make sure you have a good ground on the alligator clip.