Jacob;

Shannon's recommendation (thanks!) was a general recommendation...whether blinkers or headlights (as in the article), they all work the same: Switch applies power from source by way of harness to lamps, and current is returned by way of vehicle (metal) chassis to negative of battery. All loads employ some variation of this. Refer to wiring diagram (http://www.sw-em.com/122S%20Wiring%20Diagram.jpg) for specifics of source circuit, possible fuse, wire color codes, connectors, etc.

More specifically:
Being considered "mission critical", headlights (like IGN) are not fused, so NO amount of work on fuses will have ANY affect to bring lights back. Instrument lighting (only) is fused by Fuse 3, and often intermittent or nonfunctional because of scratchy dimmer control (turning Lightswitch knob). If your instrument lighting works when you pull out Lightswitch, great, so you now know you are getting power to the switch...if neither lo or hibeams work then, check for power into, and out of, the hi/lobeam switch on floor (yellow wire in, Red - hibeam, Gray - lobeam out), then move onto six terminal connector in engine compartment (Item 7), and finally on to the connectors in the headlight buckets.

Good Hunting