I've been chasing an issue ive been having with my 1980 mercury capri (four eye fox) with an 87 302 swapped in . As the title states most times when I press pull the stock back for the high beams the vehicles voltage drops and causes the engine to either almost or completely stall. This happens regardless of if the headlamp/lowbeam switch is on or off. Currently I've tried replacing/upgrading the alternator with a 3g alternator which charges strong at 14.5 volts and I've cleaned up the chassis grounds for better contact, neither of these resolved my issue. I currently suspect the turn signal switch is at fault (it houses the stalk for the high beams) but would like to seek advice before I throw more parts at the car.