Seems like every Pinto I own has or had issues with the front parking lamps/turns signals.  For years on my 79 wagon, the right front turn signal would cause problems.  I could jiggle the socket and clean the ground and it would be OK for a while.  When ever the turn signal light (dash) would come on when turning on the headlights, I knew I was going to have problems.  Sometimes the parking light wouldn't work but the turn signal would still work on that side.  Other times the turn signal wouldn't work.  It was wierd.  One day I was jiggling the wires and one of the wires came out of the socket.  I pushed it back it and it snapped further than the others.  So I pushed in the others and have not had a problem since. 

On my 73, the drivers light does not work at all.  No turn no nothing.  Bulb is good and the ground is clean.  Wires seem to be plugged into the socket properly?  I have not done any more debug work as this car is being stored.

Now on my 78 Cruiser Wagon, the drivers front doesn't work at all.  The socket is different than my other two cars.  The wires look to be sealed in the pulg housing where the others are removeable.  If you jiggle the bulb it will work till you let go.  The pass side was working but was dim.  I played with it and now it doesn't seem to work at all and now the dash turn signal lamp is on again. 

I am guessing the sockets are bad but I am not sure.  Any one else have problems with their front parking lamps?

Or spray with contact cleaner.