If both went out at the same time its probably a fuse. If either the left or right went out then you probably have a burnt out bulb. See sources and related links below for a light bulb list for your vehicle.
Take it to a dealer. There's no way you'll do it. Proud owner of one.
The dimmer switch is defective.
There are several things that can cause your 2003 Kia headlights not to work. The most common cause is a loose or corroded ground wire.
The switch.
High beam headlights reveal objects at a distance of at least 450 feet away. High beam headlights allow the driver to view obstacles in the road much sooner than low beam headlights.
Use your high-beam headlights at night whenever it is legal and safe.
You use low beam headlights when you're in a town or city in any location.
On most vehicles, the low beam headlights are the outside pair of lights. This is true when the headlights are side by side. When the two sets of lights are stacked, the low beam headlights are usually on the bottom.
Car headlights have to be able to "dip" so as not to dazzle oncoming traffic, they therefore can switch between a "high" beam and a "dipped" beam and thus have a dual beam.
Use your high-beam headlights at night whenever it is legal and safe.
You didn't mention if you checked/tested the low beam headlamps or not.
what about the low beam?