69 Dart conks out when headlights or hazard flasher put on

I live in slantytown with the above,and it runs great (170 CID slant six).That is,as long as I don't turn on the headlights,or the hazard flasher.Then the car shuts down.I have to then disconnect the fusible link on the firewall,and then the car will start up again.It will not start until I do this.This is a problem!I changed the voltage regulator,and ballast resister,but to no avail.I can turn the wipers on with no conking out,and the defroster also.The last time I started the car up,I turned the headlights on,and surprising,the car kept running.I shut the car off,restarted it,tried the hazard lights,and the car died,and would not start until the fusible link was disconnected/reconnected.Do I have a short in my hazard switch,and would that cause the above problems?And if this is the case,where do I get a hazard switch for a 69 A body.PS:I am only a shade tree mechanic,but if steered in the right direction with the proper diagnosis,can usually change out most things.One other thing that complicates matters.The prior owner was going to change the car into a muscle car (340,bigger rearend,etc.)He had placed aftermarket gauges under the dash.I removed them,hopefully with no complications.All my original gauges work fine.Thanks for any suggestions.