If you're running high-output lights, you're headed for trouble with the original-equipment swtich. The built-in circuit breaker isn't designed to handle that kind of load, and you'll get intermittent operation at best. I'd suggest using a couple of Bosch cube-type relays, one each for low and high beam, and just use the light switch and dimmer to trigger the relays. It's a very simple modification, and it also keeps the high-current circuits out under the hood where they don't have to travel over 10 feet or so of wire. Back in the dark ages, installing headlight relays used to be a popular modification, particularly on 6-volt systems where voltage drop was a problem.
Jerry
