As Don mentioned Jim, the original HL switch has a bi-metal contact on top that will open if to much current is being drawn. If you have poor grouinds, that is, to much resistance or if you have added something like extra lights or halogin you may be triping the contact. If the come back on after a few minutes then that's a good indication that's where your problem lies.
The original switch has brass contacts inside and they also get burned. To open them up and remake the contacts is very labor intensive. The good repop switch is almost an exact copy of the original switch and they are only about forty bucks.
http://www.classicparts.com/1947-54-Headlamp-Switch-Original-Type-6-Volt/productinfo/53-111A/ Stay away from the cheaper ones they look like they are made from old beer cans.
Denny Graham
Sandwich, IL
