Headlights

mill48

mill48

Member
Hello fellow members. I have a healight problem wherein one works and one doesn't. The headlights were installed new at the same time. I decided to take the switch down and noticed that the copper that holds the fuse was broken so I ordered another switch and installed the new switch that came with its own fuse. I checked all my connections and they seem to be ok. Could the fuse under the dash be the culprit? By the way I have sealed lamps with wires coming from the bottom of the bucket. On one lamp I have a red wire and white wire, on the other a red wire and a green wire. The one with the red wire and the white wire are 14 gauge, the one with the green wire and the red wire are 14 gauge. Does any of this matter?
 
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Mill48 it sounds like what you have installed is not the original style headlight switch for a Model A. There is no fuse on a original style Model A headlight switch. So it might be difficult to offer help. Perhaps some pictures of what you are working on may help.
 
I installed what was in the car and both lights were working. I'll have to wait until it's daylight again before I can take pictures. As soon as I can, I will upload some pictures. Thanks for the quick response.
 
Sealed beam headlights have three connections. Hi/Lo/Ground. You said you have two wires from the headlight, you need the third ground wire. How is the ground being made at the headlight? Also, have you done a voltage check at the headlight sockets? As for the fuse, if one light works then the fuse is OK.
 
Headlights can use a cross over wire from one side to the other for both high and low beam circuits. The ground can be anywhere that it can get a good pathway back to the battery but both headlamp buckets need a good ground.

Most cars that use a headlight switch like that will have a high/low beam dip switch on the floor. If tail lights are on both sides then it can use a cross over wire set in the back as well. The brake light switch will also have to be wired in if it's going to share the circuit or it can have a separate circuit with its's own fuse on the power source. Turn signals are another separate system that would share the brake light function if so equipped.

If one headlight is out then I'd ask if it has it's own circuits or if it has a cross over for just two circuits? It certainly doesn't need separate circuits for each light assembly. 14 gauge wire will work for 6-volts. If it is 12-volts, it could get by with a smaller gauge wire. I think I would use a short stop circuit breaker like Ford did in later years rather than a fuse. A person could be in a pickle some time if a spare fuse wasn't carried in the car.

I prefer my model As wired like they came from the factory with the addition of a fuse on the starter and an additional tail light.
 
The headlights have a crossover from one light to the other. I am about to do a voltage test with a multimeter.
 
I tested the voltage with a test light and got from 11.9v to 12.3 on the headlight connections. The reading on the ground was also 12.3. Is the ground good or bad with such a reading? I had the alligator clip attached to the positive terminal on the battery.
 
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The ground should be zero volts. Somehow you're feeding power to what you think is the ground. Either that or I don't understand ----- your test light gives you a voltage reading??
 
Yes. It appears to be giving me the battery reading. I tried to use my multimeter but apparently I'm not using it correctly. I have it on the ohm settting but I don't know which setting to put it on. In either case the number doesn't change from the time I turn it on. I am clipping to the negative terminal of the battery and the gound wire.
 
Some new meters use a sine wave to indicate AC power and a flat line to indicate DC power instead of just putting DC and AC on there. The automobiles are all DC but the meter can be used in the home to check AC stuff. Just make sure it's on AC voltage in the home. The 110 volt AC system may fry a DC meter circuit.
 
No, I was testing the ground. I couldn't get a proper reading because the leads were too far from the battery.
 
I eventually found out that what I thought was a new light was no good. I say that because I had a spare that I connected and the light came on immediately. I thank you all for your great advice.
 
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