8N Headlights Won't Work (Not a grounding issue)

I have a 1948 Ford 8N. I've had it a week or two with no working lights. It does have headlights and tail-lights installed.
It is a [b:5a01a4042c]6V Generator[/b:5a01a4042c] System
It utilizes a [b:5a01a4042c]negative ground[/b:5a01a4042c]

This is the way it's currently wired. The wires are[i:5a01a4042c][b:5a01a4042c] not actually this color[/b:5a01a4042c][/i:5a01a4042c], I just made them all different so people can tell me which ones to move!



My inclination is to believe that the Yellow wire should be hooked up to the positive terminal and not the negative? I didn't want to try that and fry my lights though - I don't intuitively understand DC circuits.

[u:5a01a4042c]Here's what I've done so far and what I know:[/u:5a01a4042c]

[b:5a01a4042c]Ground[/b:5a01a4042c] - It's not a grounding problem. I temporarily hooked up wires from the light threads to ground just to test it. Once I get it working right, I'll permanently install ground wires though.

[b:5a01a4042c]Switch [/b:5a01a4042c]- The switch works. It does open and close a circuit. I've tested that with a multi-meter.

[b:5a01a4042c]Blinker [/b:5a01a4042c]- I really don't know why I'd want a blinker. I don't know how to test it either. So I did take it out temporarily and connected the "Blue" wire directly to the "Purple" wires. Regardless, a faulty blinker wouldn't effect the headlights.

What's the next step folks? I don't even know how to remove the headlights. To test the individual lights, like the tail-lights, do you just test for continuity between where the wire connects and the threads?

Once I get this working, I'm going to install permanent ground wires. I'm also going to add a second switch under the original; I'll use that to power an adjustable work light off of the back!

[b:5a01a4042c]Thanks in advance for the help! You all have helped me a TON.[/b:5a01a4042c]

The tractor was originally positive ground. someone may have changed it, does it charge?

The light will never work the way you show, the wire from battery would have to be hooked to the positive post. If the positive post was to ground then your wiring would work.

Lights don't care if they are connected in a positive or negative ground system.

Let's take a deep breath and think this through. The lights are grounded where they mount. You have to have power to make them work. Therefore, connect the switch input to the hot, not ground side of battery. Nothing will work until there is power to the switch.

You can test a blinker by bypassing it.

Negative ground is ok if ammeter reads correctly and generator is polarized so it charges.

If it is - ground then the wire going to the switch should be on the + side of the batter since most lights have an internal ground in side the housing

[size=18:1e5b41d155][b:1e5b41d155]Update[/b:1e5b41d155][/size:1e5b41d155]

So I changed it so the switch is now drawing from the positive terminal. Easy fix, which is what I guessed, but the feedback certainly put me at ease making the change. I've found that:

*The blinker does work. But why would you want your lights blinking all the time, that's annoying!

*I have one bad tail-light.

*I can't figure out why my headlights won't work. They're so frozen up and secured so tightly that they're nearly impossible to take off. Is there a way to "test" them with a multimeter without taking them off? Any tricks on getting them off?

Headlights are off, and indeed bad. And holy crap they're like $60+ a piece!

You were pricing the whole as'embly. They have
replaceable bulbs just like a car , @ $15 or
less....

(quoted from post at 12:29:03 08/30/15) Sealed beam headlights are not $60. You can get them for as low as $6.00 if you look hard enough. The 6-Volt lamp is industry p/n 4019 and the 12-volt lamp is industry standard p/n 4419. Here's a link to just 8n's and the 6-V sealed seam they sell. It is a good GE Brand for $13.00. Don't know why you don't wire the system as 6-volt POSITIVE ground. Then you only need to run one wire to the lights. Some will argue that two wires are better but whatever blows your skirt up. My '48 8N is wired 6-volt, positive ground, always has been, and the wiring is exactly how it was originally. I never have any problems with lights or not starting because I keep it maintained properly -clean, bright, and tight.

Click to expand...

Yeah I finally took apart the assembly (it sure didn't want to be taken apart) and found Wagner 4511, which is a 6V beam available at NAPA. My taillights are not original, they're a hideous plastic contraption wired up to a blinker that doesn't belong on a beautiful piece of iron. My Tractor is not a trailer queen, and it's certainly not "parade ready" but I plan on putting more period authentic tail lights (and a work light) on it.

Mine was 6V negative ground when I got it - not sure why. However, there is only one wire run to each light. It grounds just fine on the fender/hood. Is there an advantage to going positive ground? And is it as easy as just flipping the battery around? Someone told me they went away from positive ground because it encourages corrosion.

You can check lamps with an ohm meter. Should have some resistance but not an open/infinity

All of the old 6 volt motors are 6v-g as it works better as far as the ignition is
concerned. All you have to do to change it is to reverse the ground and positive wires and
re-polarize the generator and reverse the wires on the ammeter.

(quoted from post at 13:47:52 08/30/15) All of the old 6 volt motors are 6v-g as it works better as far as the ignition is
concerned. All you have to do to change it is to reverse the ground and positive wires and
re-polarize the generator and reverse the wires on the ammeter.

Click to expand...

Worth a try. Anything that might help a cold MN start. Ammeter wires are still for positive ground. Thanks for the advice