MN240sx

Hey people, this is my first post so I am hoping that I have put it in the right catagory! I own a 1995 Nissan 240sx. I have a problem with my electrical system I believe. My after market head unit stopped getting power, along with my factory installed fog lamps, and the clock in the gauge cluster no longer displays numbers! I checked my fuses (even ones that I wouldn't think would be related to these) and the ones that were burned out (a 15a for the audio) was replaced but still nothing?! Everything else seems to be in working order, so fog lamps, clock display, and head unit are gettin nothing. fuses seem to be ok? Any ideas? or even better someone with a definite source of my problems!

Thanks TONS!