The answer to that is headlight relays, which switch the highcurrent from source to load without going through old wiring! http://www.robdiesel.com has a little writeup on that under the Technical Data section. ----- Original Message ----- From: "Philippe COURANT" <accf_clb@xxxxxxxxxxxxxxxx> It's the circuit breaker who breaks the circuit : too much amperage (i.e halogen bulbs or a grounded bulb or a too thin wiring) or breaker needs replacement. Don't know where is the breaker ; in '57 it's a built-in affair in the switch. I've a friend who has a '66 cad%"*ac and he has the same problem; he has halogen sealed beams and when he put high beams on, the breaker cut after 15 or 20 s.