Headlight problems.

[Ashaffer]

I have a 1983 GMC Sierra 2500, a couple weeks ago the headlights started doing weird things like flickering or switching from high to low beams or shutting off completely. (of course when I am on a dark country road while its pouring rain.) I figured the dimmer switch on the floor was bad so i shot for overkill and bought new dimmer switch, new headlight switch, all new headlights and bulbs all around and I took a wire brush to all the contacts and got all the corrosion off and put dialect grease on all of the contacts. well the problem seemed to be fixed but on my way home from work they started flickering again. I figured there must be a short so i spent the whole day chasing wire looking for a short in the wiring. i found one and fixed it. the lights worked fine for about a week then they started flashing again, just the headlights all dash lights marker lights and tail lights work just fine. so now im at a loss and have no idea what else it could be. any ideas? oh and if i shut the lights off for about ten seconds they come right back on but that only last for a minute or two. and when you first turn them on the problem doesn't come up for probably close to ten minutes