e mail us some of the majic smoke and we will see if we can find the source.
If it is in the cab it is the switch. The bulbs don't need to be replaced. If it comes from under the hood it might be
1) lamp sockets
2) fuse holder arcing
3) hot wires ( hot means heat in this case)
if you know how to handle a Amp meter check the current when the high beam light are on.
