Cub wiring harness - school me on 4, 6, 8 wire

Hotflashjr

Well-known Member
Location
Western MA
I have a 1948 cub with front lights, rear combo light. Prior owner put in a new wiring harness but didn’t hook up the front lights. Lights are a single wire hook up but it looks like I have a ground and power wire coming out of the pigtail. I’m guessing I have the wrong harness first and second this is a 6 or 8 wire and I likely need a 4?
 
The lights can be grounded to the chassis of the tractor, you don't need to run the ground all the way back to the dash or battery. The other wire (positive if negative ground or negative if positive ground) will be connected to your wiring harness wires that go to your light switch.

The wiring will be similar but different, depending on if your tractor is the original 6v system or 12v negative ground.
 
If everything is original as you say, then you could just follow the original factory wiring schematic. I tried to link a photo of it here but it didn't work out. There is a website specifically dedicated to cubs if you search. I have a 1948 cub myself, but it has been converted to 12v negative ground and distributor with electronic ignition.
 
The later models had a ground wire running to the lights. Your 48 does not need it. A 48 would have originally had a magneto ignition and a cutout on the generator and the charging controlled by the HI Lo positions on the light switch, and would have used the 4 wire harness. You can use the harness you have, but if you still have a cutout rather than a regulator you need a wire from the F lead of the generator to the charge position of the light switch it may not have.
 
Personally I think either a dedicated ground conductor or the chassis ground will work just fine as a functional choice.

Its possible the hood on the Fcub doesn't have a great ground path back to the main chassis engine/torquetube/axle, its just sheetmetal secured to other sheetmetal on my tractor, and if everything is pristinely painted it might be a high resistance connection, where the conductor would be a better choice.

Imo the ground conductor can probably share the load between the two headlights. Or, run pigtails from a point on the "heavy metal" chassis up to the posts for the headlights.
 
if your gen still has the cutout you need four wires one for the mag or dist 2 for the cutout and one for the lites
 
So going and looking at the tractor I had a hard time getting my head up under that hood. I have a generator with what looks to me like a voltage regulator on it and not a cut out. So I have a 6 volt, positive ground, with a voltage regulator and I believe a 4 position switch. Far left is low charge, next is high charge, then driving lights then work lights.

Used to JD's where the regulators are typically mounted off the generator and cut-outs were on the generators.
 

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