I've got a 91 Integra LS that the headlights and corner bulb ( the one that stays on with parking light & signals, doesn't work). Both headlight fuses are good, headlights bulbs are known good, connections are good.
I know the combination switch is still good b/c the foglight doesn't work till i click it to the headlight setting ( meaning it still supplying 12v pos to energize the foglight relay ). if i leave it on the headlight settings and click on hi beam, hi beams will work.

This happened with the car was idling, i wasn't sure if alternator was good or bad and didn't have a voltmeter so i remove the neg. the car still idle and when i put the neg back on, the headlight ( which was on at the time ), shut off and the engine died. Turns out the ECU fuse kept on blow'n....i had to replace the ECU. car fires up now but headlights is still out!