Headlights

I have a 1989 toyota mr2 supercharge. I turn on the headlights and they come on, then all of a sudden they go off, at first I giggled the switch or held it in and they would come back on. As time past they went off more. I took the part of dash off so I could see switch better, but don't know what im looking for. What would make them do this? Do you think I need a new switch, or it could just be a loose connection? Where do I start? And they do come up as they should , just flicker on and off. Sometimes they stay off. But eventually come on, then off again. Thank you for your help,   Sincerely, Delilah Schorr [email protected]