Where would the voltage step down from 24 to 12 for lights and guage? In looking at the service manual it almost seems like it should at the switch. When I trace #13 wire (fuel guage) back to source, which appears to the switch, it?s at 24 volts. Same as the cigarette lighter wire. Thanks.
- Thread starter Price140
- Start date
Olliejunkie
Well-known Member
If its original basically half the lights run on one battery and the other half the other battery one half is neg ground and the other half is pos. I'm not sure but I think the light switch may be part of it. Some one else more knowledgeable will probably come along.
wore out
Well-known Member
The midpoint of the two batteries is connected to the chassis.
As it left the factory, the RH battery supplies (+) 12 volts to the terminal on the engine block side of the starter "belly", the LH battery supplies (-) 12 Volts to the upper post on the starter solenoid.
The (+) 12 Volts and the (-) 12 Volts are "seen" by the starter and generator as 24 Volts.
From the battery connections at the starter, the wiring harness takes (+) 12 Volts and (-) 12 Volts to the light switch, by way of the key switch and a pair of circuit breakers.
The light switch is two switches in one, it runs half the lights (more or less) from the "BATT A" (+) 12 Volt supply (brown wire), and the other half (more or less) from the "BATT B" (-) 12 Volt supply (blue wire).
NOTE the path of the brown and blue wires and what they are connected to, that is the secret to how all this works... operating 12 Volt lights on a system that charges at 24 Volts.
Tx Jim
Well-known Member
- Location
- Coyote Flats, Texas
I agree with what wore out stated. Originally your 4010 had the woven rear battery cables as shown in his photo. Later JD engineers decided to utilize a cable connecting both rear battery posts(see photo below) so as to give better connections. With this updated battery cable system there needs to be smaller wire(item 30) or inline fuse to split the 24 volt system to provide 12 volts for lights & fuel gauge. If your tractor has been updated then """Check connections on this small wire""". Both ign & light switch have posts marked batt A & batt B each supposedly furnishing 12 volts.
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