Alfa Romeo Repair: Electrical problems, left turn signal, left blinker

Question
Stephen,
my '85 Alfa Romeo Graduate is acting in a most peculiar way regarding the rear lights, with the headlights off everything works fine but when they are on, my left blinker and parking light both blink when I use the left turn signal and my left parking light and the right blinker both blink when I turn the right blinker on. I would greatly appreciate it if you could steer me in the right direction with this puzzle.
Rick

Answer
You have bad grounds.  Specifically the black wire at the headlights needs to have its connection on the body cleaned.
Best is to remove the ground wire bolt and clean the surface with sandpaper the apply a dab of an anti-seize compound and reapply the bolt.  The lazy way is to loosen the bolt, spray WD-40 and retighten the bolt.  

Now is the time to attend to all the ground attachments on the car and also clean both battery terminals.