1993 Ford Tempo Headlights

You replaced alternator because you were thinking or someone suggested that to much voltage is blowing bulbs? But why wasn't to much voltage blowing everything electrical including other bulbs? Does the car have daytime running lights? Seems like that would be the only culprit capable of blowing just the headlights. Just mt 2 cents on it. I personally have never heard of such a problem. If your alternator was overcharging it would trigger the red dash light warning. Usually a temporary on off condition or flickering. The only other cause of headlight failure is vibration or moisture(water) on the bulbs. You might want to change your dimmer switch too.