48 8n headlights troubleshooting

cersbo

New User
Hello, neither headlamp works. Rear light does work. Looking for some trouble shooting pointers. Can"t seem to get any reading on my voltmeter. I am a newbie and not electrically inclined. Thank you all in advance!

Chris
 
Most of the time its improper ground. Run your pos. through the switch then fuse to the light. I don't trust the ground so I return the neg. to back to the dash and secure a good ground. Make sure you're getting fire to the light.
 
a lamp circuit is the second most basic circuiot in existance. A shunt or short IS the most basic.

a shunt / short it pretty much a wire from bat post to bat post.

A lamp is only a lil more technical. it's a wire from hot to a lamp to ground. sure. throw in a switcha nd a fuse. those are invisible to the circuit for all intents and purposes until you open the circuit.

use a test lamp and check to see if you have power to the wires feeding the lamps.

clip the test lamp clip to chassis.. then probe before and after the switch. might be bad connections.

rusty 60 year old tin is NEVER a good ground. I always run a seperate clean chassis ground to my headlamp buckets.
 
Bingo.

I route a dedicated ground wire to the headlamp mounting bolt on all of my vintage Fords. Works flawlessly.

Dean
 
I agree with the others that a bad ground is the likely culprit.
It's also possible you have two burned out headlights.
You could measure the resistance across the lights, (unhooked)
or hook one of them to the rear light wires to test it.
If you're rewiring, I would put the fuse between the battery
and the switch instead of after the switch.
That would protect against a damaged/wet switch as well
as a fault at the lights.
 
Well, many feel more comfortable running two separate wires to their lights and that's fine. Me, I run a good quality wiring harness and be sure to clean the area behind the mounting areas for the lights on the inside of hood. There is a steel backing plate for the headlights that snugs up to the metal there when lights are fastened, and the hood and plate need to make a good electrical connection -i.e. bare metal is best -no painted surfaces or crud buildup. Then, the headlight 1/2-20 hex nut and lockwasher will guarantee a good connection once tightened down. I have never had a problem with my lights using the original one-wire harness method of connecting and I have used my 8N for many night time projects either mowing grass, plowing or discing a field, or plowing snow, and my lights have never failed me. To each his own. As mentioned, you can first try to test the lights to be sure they are not burnt out. Remove bezel, take out lamp, connect wires/test leads from battery to each lamp terminal. Illumination will determine that it is good. Not typically likely you get both lights burning out at the same time UNLESS -you have a 12V battery and are using 6V lamps---so, without this information, I have given you just about all I can offer. FYI -6V sealed bean lamps -p/n 4019...12V sealed beam lamps -p/n 4419.

Tim 'PloughNman' Daley(MI)
 

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