High/Low Beams

try this, i am guessing you have single sealed beam headlights, i did this on my 92 chev truck, it has 4 headlights, but it is worth a try with yours.  Using a relay, splice terminal 87 to the lo beam wire, 86 to the hi beam wire, 85 to ground, and 30 to the 12v positive of the battery. the hi beam wire will act as the triggering voltage to energize the #87 terminal sending the 12v from the batt to the lo beam bulb or filament in your case. let me know how you make out.