The headlamp switch has a built in circuit breaker that protects the headlamp circuit. The dash lights and tail lights are almost always on the same circuit and protected by a fuse, no matter what the American manufacturer. It it were just the headlamps, I would immediately look at the floor mounted dimmer switch as the culprit, however, when you throw into the mix then, I am with everyone else calling it the headlamp switch. The one thing that does bother me is the tail-lamp circuit, because that should still work even if the circuit breaker has gone bad. Before you do anything else, check to see if the electrical plug to the headlamp switch has come loose. If that is tight, then check the plug on the back side of the fuse block to see if that might be loose. Usually that is on the engine side of the firewall, and the fuse block on the inside wall of the fire wall.
I also wouldn't discount there being a ground problem. I suggest that you take a jumper cable and clip it to the negative terminal of the battery, and then clip it to the engine block, and see if the problems go away. If they persist, then try clipping the jumper cable to a shiny surface, such as a bumper or some bare metal of the body. Bad grounds can cause many gremlins in the electrical system.
If you have to change the headlamp switch, disconnect the battery, and then reach up to the top of the headlamp switch from under the dash. On the top or side of the switch, you will feel a small button. Pull out the headlamp switch to the headlamp position, and then depress the button, and continue pulling on the knob. The headlamp knob will now come out fully, so you can access the nut behind the knob. Unscrew the nut with a large screwdriver, and then lower the headlamp switch. Disconnect, and take it with you to the auto parts store to match it up to the new one. Don't trust the parts book to get you the correct one the first time. Too many mistakes in the new electronic parts books.
