<VV> Seeking diagnosis - front lights not working - '66 Corvair

[Brent Fullard]

I would appreciate your thoughts and suggestions.

Here is the condition I am faced with:

(a) Both front parking lights not working - however rear parking lights do
work

(b) Left front turn signal not working - however other 3 turn signals work.

(c) Headlights do not turn on - however high beams do work.

Here's what I have checked in an attempt to diagnose these problems:

(1) Parking light bulbs are correct dual filament bulbs (and both filaments
are intact for both bulbs). When I switch bulbs, left side to right side,
problem (b) still persists, leading me to conclude it's not the bulbs at
fault. BTW: The housings are like new and have zero corrosion.

(2) I placed a separate back-up ground wire on the left lamp housing in an
attempt to solve problem (b), but it had no effect.

Any thoughts on what the cause of these 3 conditions could be? Is this being
caused by one problem or two separate problems? Is the headlight switch
potentially at fault? If so, how do I bench test it? What else could this
be?

Thanks!