I have had issues with my '05 since new. On occasion, the headlights remain on after the switch has been turned off. No other lights but the headlights. I have to then turn the switch back on and off again to make the lights go off. Also, I notice my highbeam indicator light on my dash flashes very, very quickly (easier to see in the dark, with all lights off), with the headlights on or off. This however happens so quickly, that the headlights are not effected.

 

If you turn your engine off, then your headlights, the headlights will remain on for a preprogrammed time (30 or 45 seconds, I think), then will go out. This allows you time to get into the house or turn on the garage lights or whatever. If you turn your headlights off, then your engine, your lights remain off.

If you leave your headlights on, turn your engine off, lock the doors and go away, your headlights will remain on for a set time (might be the same as above). The difference here, is when you return to your truck and use the clicker to unlock it, all the lights turn on when the door unlocks.

These are "Features" on my '03. I dunno about the flickering highbeam indicator.