Low dim lights not working

I was driving home lastnight from work and suddenly both my dim headlights stopped working. I pulled over and couldn't seem to fix the problem so I used my front fogs to drive with until I got home. Today I tried resolving the problem. I've checked the fuses in both boxes and also the bulbs and all is fine. Also the full beam is working and the rear side lights are fine. I was wondering if anyone could advise on what the problem could be??.