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6 volt headlights

I am trying to install a 6 volt sealed headlights in a 1936 dodge (positive ground). Currently there are 3 wires going to each headlight from the harness. Wiring diagram shows 1 to the high beam, 1 to the low beam and 1 to the parking light (which will not be used because seal beam covers old parking light bulb. The new 6 volt sealed light has 3 prongs on the back. The new connector has 3 slots. My question is how do I wire these?

The common terminal will have to go to the positive ground. The low-beam terminal should go to the switched low-beam (negative) power. The high-beam terminal should go to the switched high-beam (negative) power.

I think that you are somehow missing the common ground wire on the wiring diagram you are looking at.

Hey, Thanks for the quick response. But… can you explain it again for me and just imagine your trying to explain it to an idiot. Common terminal? Switched low beam? I’d really appreciate it. Pete

The polarity(+/-) doesn’t matter. Incandescent lights will operate the same regardless which way they are wired. There are three wires and three connectors on the headlight. One is the ground for both filaments and the other two are the high and low filaments. Connect the ground wire to a good, convenient ground and experiment with the dimmer switch and the headlamp to get the wires connected correctly there.

Just to add a little bit to RK’s explination.

There are two filaments inside the bulb and one end of each them is tied together. That connection point is usually tied to the middle terminal of the light connector and is the common or ground terminal for the light. The other two ends of the filaments are each tied to switched power to turn on either the low or the high beam filament.

Using all information recieved from above posts this is what I did. I used my 6 volt battery charger to find the high beam and low beam terminals on the back of the bulb, I assumed that the ground was the middle one, which it was. Then I just wired the harness wires to their corresponding terminals and used the 3rd (parking light)wire as the ground. They work but 6 volt lights, as you probably know aren’t that bright. I have a relay which is suppose to increase their brightness but won’t try to wire that until next week. Thanks everyone.

With the engine off there is just 6 volts +/- available and the lights will be dim and yellowish. With the engine running the voltage at fast idle will be 7.5v +/- and the lights will be significantly brighter. “Mazda” bulbs were the best light available for the pre-war cars it seems. I hope you are able to restore your Dodge to your satisfaction and enjoy it. Many pre-war cars went to scrap drives and many that survived the war didn’t survive the years since. I really appreciate a classic in original condition. I have just missed a couple of deals on Model As. I guess there are quite a few who appreciate those old classics and they get picked up quickly.

I agree. My Dodge is 99% original. I couldn’t see it any other way.

6V systems are very sensitive to loose/corroded connections, so make sure everything’s clean and tight. Some folks use 8V batteries to give the system an extra boost.

Normally, they stink for light output. Yours will be really bad because you grounded them through the parking light supply wire. Wire to chassis ground and you should see a noticeable difference.