Basic High/low headlamp wiring question

I have a royally messed up headlamp system/wiring for an 82 amc spirit

The headlamp system is the large blocky seal beam system....with 4 headlamps total....

Now the high beam pair of lamps is simple....it only has 2 prongs so it is either off or on....

On the other hand the dual filament low/high beam bulb has me stumped....

It has three prongs and I am not sure which one is supposed to be ground, low positive and high positive...

my GUESS is that the third prong off to the side is supposed to be the ground and the two prongs opposite each other are high and low....

Now when I power up the headlamp THAT way i do get an obvious low(er) and high(er) beam.....seems reasonable...

BUT the odd thing is if I just run power across the two OPPOSITE prongs rather than nothing I get an even a HIGHER (brighter) beam....

So I am thinking right that the prong off to the side is supposed to be ground?

BTW the headlamp is a H4656 (2A1) style headlamp....

THANKS for any pointer!

You are turning on both filaments by running them that way. Yes they are bright together, but that will load up the headlight switch and smoke it out pretty fast.

The two outside pins have a common point which is the ground or center pin so applying power to one side and grounding the other side will light up both filaments.

Power to either side pin and ground in the middle, gets one filament at a time lit up.
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

I guess I didn't describe that right. He sure sounds like he is firing up both filaments with whatever two pins he is hitting....
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Rotate the headlamp so that as you look at the back of it, the terminals appear in this orientation:

No. There is no sealed beam that has the center pin as ground.

thanks for the quick response!

And thanks for the asc art Daniel!

Another quck question...

In the dual filamament headlamp.....when it is being run on the high beam setting.....should BOTH the high beam and low beam filaments be on at the SAME time or JUST the high beam filament?

thanks again

take care

I just checked my auto repair info system- it only goes back to 1983 but it should be the same as your '82 (since it was the last year for the Spirit).

Anyway, my wiring diagram only shows the high and low positive feed wires (White and Light Green respectively) running out of a dimmer switch. On old cars the dimmer switch was seperate from the headlight switch, usually operated by foot or lefthand column stalk. I'm going to guess that yours is an "either / or" switch.
This would mean that you get either 2 low beams or 4 high beams, never
6 all together. That would be the safest way to wire it up anyway.

I've seen different cars do headlights different ways but I'm willing to bet that your dimmer switch is just a toggle.