wiring problems...

i posted before about wiring problems in my 1980 Toyota pickup, which before i had the truck not starting. I replaced the alternator, and voltage regulator, which seems to be working fine...except i have to charge the damn thing ocasionally. but anyway at times both headlights will work, and then just one, i checked the wiring and everything seems fine, but i dont know. also since i put those new parts in my speedometer, tachometer, and others do not light up, and the tach does not work now. ANY HELP WOULD BE APPRECIATED....