You have dirty contacts inside the light switch, or a partial ground at the dimmer switch. The headlight switch has a built-in circuit breaker that allows the lights to go out momentarily and then flash back on, rather than blowing a fuse and going out altogether. Inspect the wiring harness from the switch, to the dimmer, to the headlights for bare spots, and you'll probably end up replacing the headlight switch, and possibly the dimmer as well.
Jerry


"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!