So I have a 89 b2200. I was headed home on Wednesday and I started to smell burning plastic. My running lights and interior light are out. I replaced the burnt wires and replace a couple of fuses and still nothing. I'm needing a little bit of help. It would be greatly appreciated.
The headlights themselves are on a different circuit than the interior light/running light circuit. It's not uncommon for the interior lights, front parking lights, and rear tail lights to all go out together, this is due to carbon build up in that part of the lighting switch. Axel Breaker posted a how-to to clean these up and restore. See http://www.mazdatrucking.com/forum/showthread.php/13002-Head-light-switch-information
This also happened on mine, about 5 years ago now, and I have a separate toggle switch under the column for switching on the running lights and instrument panel lights. "Someday" I'll either clean up my switch as above, or swap in the used part from my spare combination switch.