Problem w/Headlights

I have a 1993 Honda Civic DX, 108K miles, 1.5L

When I get into my car to go home from work at night, I turn the engine on and switch on the headlights. After about 30 seconds, the headlights turn off on their own. As I continue to drive, the headlights turn back on for about a minute, then turn back off for another 2-3 minutes. This pattern continues for about 15 minutes, until the lights finally stay on for a solid 20 minutes. It's happened the same way every single night for the past week. I took it to a shop that specializes in auto electric work and they check the battery and all connections and found no problem. After reading alot online, I've come to the conclusion that I may need to replace the headlight switch. The bulbs are fine, the wires are good, normal battery and good fuse. Is there anything else that could cause this malfunction other than the headlight switch?