| Barney | -- 10-30-2025 @ 1:17 PM |
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Hello again, I have a 1940 Ford standard; original 6 V system, positive ground. Thank you for all your inputs of suggestions for my recent post of a whimpy headlight situation. I'm convinced I have good grounds; very important with 6 V systems. I either have some "bleedthrough" some place that I haven't located, or, the following: I connected a headlight directly to the battery; to the ground terminal and the low-beam terminal, there's nominal 6 volts. However, without changing connections, there's a bit less than 4 volts at the high-beam terminal. I would think there should be 0 volts there. I'm wondering if I have defective sealed beam headlights. They've never been as I think they should be. They are Wagner brand. Thoughts? Thanks very much. In a previous post, I stated I wouldn't whine anymore. I lied! Regards, Barney
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| ford38v8 | -- 10-30-2025 @ 2:27 PM |
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Barney, I'm not following your description of connections. Let me start from the beginning, and request that all your responses to a question be on the same thread, only create a new thread for a new question. Threads drop down lower on the list as they get older, so just scroll down to find it and your response to that will bring it up to the top. OK, to your question: Ensure that your headlight ground is connected directly to the frame of the car, not just the fender. Next, test your ground at the headlight against a live hot side from the battery, connected directly. This will confirm that your ground is good. It should read the same as your battery itself. Next, test your hot line going to the headlight at each junction. You should have negligible voltage drop, total about .03 less than the battery. Your most serious drop will be the hi/lo beam switch, so bypass that to discover good voltage at the headlight. If it is faulty, work it on/off a few times to clean up the internal connections, and replace it if necessary. An excellent connection can be made with a relay system, but no need to do that if you can tune up your present system. Alan
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| Barney | -- 10-31-2025 @ 4:42 AM |
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Good morning, Alan, thanks for the advise / instructions regarding the threads; makes it easier to follow. 1940 Ford V-8, 6 VDC, positive ground. Bench testing the headlamp: 1. Connect a lead directly from the + post of the battery to the ground terminal of the headlamp. 2. Connect a lead directly from the - post of the battery to the low beam terminal of the headlamp. The headlamp is now illuminated. 3. Connect a VOM across the ground and low beam terminals at the headlamp; 6.1 VDC. 4. Without changing any wiring, connect the VOM across the ground and high beam terminals at the headlamp; 3.8 VDC. This does not make sense to me. I would think it would be 0 VDC. Does this make sense to anyone? Thank you for your comments. Regards, Barney
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| GK1918 | -- 10-31-2025 @ 8:03 AM |
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Yes that should be -0- are you sure the ground is on the correct spade on the bulb ? If I remember (thats rare) looking at the back of the bulb the left spade is low beam, top spade high beam and right spade is ground in all voltages or polarity. Most bulb grounds are connected to the headlight bucket (body ground) from there fire wall ground cable to the intake manifold. step 2 strong power out from head lite switch 3 same good power at the dimmer sw. and 4 the same strong power out of dimmer sw. And checking this power Check with a good load THEN use the voltmeter. You may be surprised with voltage drop from dimmer to the load. My car headlights dimmer than a candle was the light switch my fix a toggle sw. for now hot wire to toggle and toggle to dimmer because for me ; replacing this switch is worse than extracting head bolt LOL
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| Barney | -- 11-03-2025 @ 6:10 PM |
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GK, Thank you for your suggestion of the locations of which terminal / spade is ground, low beam, and high beam. I did not have them as you described. I assumed (y'all know what that means) that the top spade was ground. I'm looking forward to seeing the difference. Thanks again. Barney
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