floor dimmer switch question

[Dwight Romberger]

Hi All,

I am rewiring a '36 International pickup. I have to replace the floor dimmer switch. Am I correct that when you turn on the high beams, the low beams should stay on?

I am having a senior moment.

Thanks,

Dwight

[ply33]

...Am I correct that when you turn on the high beams, the low beams should stay on?

On all the cars I've had the low beams turn off when the high beams come on.

[Guest Oldengineer]

On my 48 Chevy, the low beams go off when I click on the high beams with her floor dimmer switch.

Regards;

Oldengineer

[Marty Roth]

I agree with the above - they are, and should be, entirely separate circuits. Either high, or low, but not both at the same time.

[PONTIAC1953]

all three of the replies are correct, never should you have both low and high beams lite up at the same time, charles coker, 1953 pontiac tech advisor.

[Rusty_OToole]

With dual headlight systems don't the low beams stay on?

[ply33]

With dual headlight systems don't the low beams stay on?

Been a while since I've had such a vehicle, but I recall the "always on" bulb had two filaments. One for high and one for low. But its been over 20 years since I last sold the '63 and I could well be remembering wrong.

[Dwight Romberger]

Rusty,

With dual headlights I remember the low beam bulb always stayed on. If all four bulbs were on, you knew the person coming toward you had their high beams on!

Dwight

[ply33]

Rusty,

With dual headlights I remember the low beam bulb always stayed on. If all four bulbs were on, you knew the person coming toward you had their high beams on!

Dwight

Just did some digging: For the 5 1/2" diameter sealed beam lamps used in the quad or dual headlight setup there were two different bulb numbers: #4000 which has two filaments, one for high beam and one for low. And the #4001 which was a single filament bulb for high beam only. On high you had the high beam only light on and the high beam filament on the #4000. For low beam you had only the low beam filament on the #4000 on.

#4000 and #4001 were superceded by other numbers with higher output but the same filament setup.

End result: The high and low beam circuits are totally separate. But when looking at the lamps one pair is always on (either high beam filament or low beam filament but not both at the same time) and the other pair is only on for high beam.

[Marty Roth]

ply 33 is correct

4-headlight systems, or Quad-as it was also called - typically the outer (#4000) pair, or the upper pair when stacked, were dual filament - both high and low beam, and the lower (#4001) pair, or inner pair were the high beam only.

When low beam was selected, only the low beam filament of the 2 dual filament bulbs were energized and lighted.

When high beam was selected, the high beam filament of the 2 dual filament bulbs were energized, as were the single filament ofeach of the 2 high beam bulbs.

Both high and low were not lit together - It only appeared that way because the #4000 had both filaments, much the same as the earlier style 7-inch sealed beam lights.

It is interesting, that the earliest electrical headlights were a combination of bulb-reflector-lens.

Effective with the 1940 Model year, it was federally mandated that new vehicles had to use the 7-inch sealed beam with dual (high-low beam) filaments. This was supposedly due to poor lighting resulting from the "old" system having issues with condensation, bulb-aiming, and diminishing quality of reflectors.

Now, our "new" models have a modern bulb, sometimes quartz-Iodine/halogen/someother state-of-the-art, with a reflector made of plastic, and a plastic lens which clouds over within a few years, drastically diminishing the quality of light projection. That never happened when my "PRESTO-LIGHT-TANK" fed acetylene through a rubber hose to the headlights of the 1912 Oakland, I just had to be careful to use a loooong match to "Light The Lights". The tail light was kerosene, and used a wick. We were modern, since the earlier cars used a carbide generator, sprinkling water over carbide flakes to create an explosive gas.

[Dwight Romberger]

Just when I thought I knew something. Oh well.