Headlight help

matthon said
Both my low beams blew out in the bulbs.

It's a line voltage spike that did a job on your low beam filaments -- the glob of molten tungsten at the end of the filament support is the giveaway. Sounds like your voltage regulation is not what it should be. Are you running relays in a setup anything like this? Or just running your H4 conversions on the stock wiring?

assumption is the dash switch grounds the headlamps, is this correct?

No. The dash switch sends power to the beam selector kickswitch on the floor, which then sends power to the headlamp low or high beams. They are grounded permanently (via cheesy sheetmetal grounds).

I actually ran a ground wire from the dash to the gauge cluster because 2 of the dash lights were not working, and that solved it- those little screws holding the dash in are a poor ground at best- and I didn't even realize the light switch needed to be grounded.

It's adequately grounded via its metal-to-metal mounting.

I'm staring at the wiring diagram and I can't believe I wasted $45 bulbs.

Those are Philips Xtreme Power H4s -- the best standard-wattage H4 bulb made. But they, like any other bulb, will not withstand a high line voltage spike.