1960s Turn signals, lights haywire 1966 Deville

[66DevilleRagtop]

I really could use help. Suddenly my turn signals stopped working and nothing makes sense.
Both front turn signal lights do not work. The hood indicator light works on the right. The right rear turn signal works. I could go on, none of it makes sense. The right high beam does not work. The high beam floor switch does not work.

Am I missing something obvious? Does this sound like something familiar to you all?

[Julien Abrahams]

I would start by checking the grounds. The headlights and front turn signals rely on the same grounds. Cleaning them does not hurt. Bad grounds can give really weird symptoms which may seem illogical. Do that first. And I would check the fuses.
The high beam switch problem might be related to the ground (if the headlights do not have a proper ground, it will not switch to high beams). But it could also be occurring at the same time and be unrelated to each other. 

[66DevilleRagtop]

I would start by checking the grounds.

Where do I check the ground on the turn signal - as I have the turn signal out, do I simply light sand the area where the housing bolts to the chassis? or is it grounded through the wire? Also, how do I confirm a ground, by placing a test light on the housing/bulb socket and the other side of the test light to a positive terminal of the battery?

Secondly, the same on the headlight, I have the headlight housing off and accessible, how would I check the ground there?

The fuses look good, but I will pull them anyway and replace just to be sure?

I will order a new bright foot switch just to eliminate that variable.

[Julien Abrahams]

I would just check the fuses. If they look okay, they are probably OK. Do you have a multimeter? Then you can simply check the fuses when they are installed in the fusebox. Just check for continuity.
The headlights are fused via the headlight switch circuit breaker.
Do you have a shop manual/wiring diagram? If not, I would advise to get one. Always comes in handy.
If you don't have one, I can post the wiring diagram here. There you can also see where the turn signals and the headlights ground.
From the top of my head, the turn signals ground through the housing. So clean the attaching bolts/nuts.
Please let us know what works and what doesn't. If the right indicator bulb and the rear right turn signal work normally, it could be something as simple as a faulty bulb in the front turn signal. (And then you also know that the flasher is OK).

[Julien Abrahams]

Did you manage to trace the problem?

[69Deville]

Grounds are the first step. The front turn signals ground through the housing which can give you issues. I had to add a ground wire off of the housing itself to solve a similar problem.