need an assist here -

brake lights and turn signals and hazards work fine with headlights off.
as soon as you turn on headlights, headlights seem to be fine but tail lights dim in and out intermittantly and turn signals blink fast - similiar to what i remember (old school) happened when a bulb was going out or had gone out.
about a year ago i did repair a loose wire on the turn signal assembly on the steering column to fix the brake lights but this is a new issue.
no fuses blown and no other issues i know of elecrically. we have had the occasional dead battery, but that can be attributed mainly to my 17 year old son and leaving stuff on.....

could this be an alternator issue or possibly an issue with the turn signal assembly again? i am hoping it isnt a short or something along that line -

hopefully someone has an idea or has heard of a similiar issue - thanks for your time and info

ted