I have a 60 half ton. My ? is. When you have your headlights on and then hit the dimmer switch are all four lights supposed to work or just the brights. It seems that I've seen all four work on the older rigs. Is it robbing power away from the bright side by the dim also being on? Would it help to isolate from one to the other?

 

on all no matter who made it , the old iron i've had with quad lights they all worked on high beams .

 

All four lights should be on in high beam. If you're worried about "robbing power" then connect them through seperate relays...one relay for low beam, one relay for high beam.

You can get a universal headlight wiring crossover from LMC Truck for about $40.00. It has 2 relays for the headlights as well as parking/turn indicator wiring.

 

All the 4 light systems I ever had turned out the lows when the highs came on. Even our new vehicles with factory fogs turn out the fogs when you switch to high beams. They used to sell an aftermarket setup back in the day to convert them so all 4 came on. Really overkill IMHO, the lows will not add very much to the much brighter highs with stock bulbs.

 

The answer doesn't seem to be simple. I looked up a '58 Ford (car) wiring diagram on The Old Car Manual Project (http://www.tocmp.com/tOCMP/wiring/57...re5765-196.jpg) and it shows that the Low beam bulbs had two filaments, one of which is on when High beams are on. So in that case all 4 would be on when High is on. As I recall, there were Low beam bulbs that had two prongs and some had three; but my overall recollection is that all four were on. Low beams to light up close, High beams for further out.

 

I have a motorhome out in my driveway with quads, I don't know about fogs but I can assure you all four lights are on on high beam. It makes no sense to wire the dimmer to shut off and on the low beams when a simple on-off switch for one set of lights would do.

If the low beams shut off when the high beams turn on or vice versa there would be a blink in the lighting...that simply is not the case.

 

You don't want to miss anything. You need both during bright selection. The high beams for deer and the low for rabbits,beaver, squirrels, etc. Road kill is the best meal of the week, it's free and mostly fresh. Have a great holiday, chuck

 

The answer is simple and logical. If they were wired so the low beams were off when the high beams were on, if both high beam lights were burnt out or otherwise inoperable, when you hit the dimmer ALL the headlights would be out causing total darkness and panic.

Besides that, doesn't anyone else remember "back in the day" seeing cars/trucks with 2 lights on on one side and only one on the other?

 

On the '57-'60 FoMoCo trucks, ALL four (4) Headlights are ON after the Dimmer Switch is activated for the Highbeams & as A.F-1 stated, the Low Beam has two (2) filaments so that they stay on w/ the Highbeams engauged.

 

Hmmm. In the early teen years which approximately coincided with the 4 headlight era, we played a adolescent couples game we called "padiddle". If you saw a vehicle with a headlight out while with your honey, you called PADIDDLE! if the guy called it first he got to kiss the girl, if the girl called it first, she socked the guy. I remember being on the giving and receiving end of that game many times, but I cannot recall ever seeing a vehicle with 3 headlights or 2 on one side on. I know for a fact on my 67 Tempest the low beams went out with the high beams on. I had replaced the automotive sealed high beam bulbs with aircraft landing light sealed beam bulbs.

 

I just did a google search and the #4000 sealed beam bulb for a 4 headlight system was 3 prongs but low beam only.

 

Why would it need 3 prongs for low beam only?

 

dunno thats what it says.

 

One is for ground, the other two have to be for filaments. It doesn't sound like anything that would be switched off when high beams are switched on.

 

on my 60 ford, all 4 lights are on with the high beam.

the circuit for the two lights (hi and low beam on) are in series, that is the power goes thru the high beam, over to the low beam and then out thru ground, therefor the need for three prongs. so if the hi beam burns out the low beam light will not be on since the circuit is broken.

the low beam circuit goes thru the other prong and out thru ground.

rgds
Mike