this is urban legend, i think. street-legal headlights are limited by law to 55w max, and it doesn't matter what type they are. legal halogens aren't noticeably different in this respect than the old sealed beams. where they are different is that the halogen process
Yeah, but 30+ year old headlight switches are often all crapped out. About half of the ones I see are semi-melted and show signs of the push-on connectors overheating. Just fixed the 72 hornet's switch!
So there's a statistically significant window of opportunity that the switch dies a day/week/month after installing halogens (or regulars, or small stuffed chickens, etc), just proximity.
I can distinctly recall some time in the early 1990's, pulling out of the last tiny town in AZ on I8 West onto the freeway, and the light switch burning up for the last time just as I'm coming up to speed on the onramp in the dark. No Fun. Alligator clip from the toolbox got me home.