Farmall B wiring harness

Shopping for a wiring harness for a Farmall B. It is listed with our without cutout. Can someone tell me what they are talking about.
 
A cutout is a component of the charging system. Probably most early Bs had them. They are a relay controlled by voltage that disconnects the generator when the tractor is shut off, preventing the battery from discharging. As the tractor starts, the generator self excites and begins to put out more volta than the battery. The cutout latches its contacts letting the voltage get to the battery. Charge rate (if equipped with lights) has two settings low charge and high charge. The light switch controls this with 4 positions. LHDB Low charge, H High charge, D dim lights and high charge, and B bright lights and High charge. If no lights (from the factory) the cutout will have a wire connected to the field terminal on the gen that makes a low charge all the time. Field circuits are ground based. The Light switch grounds the F terminal on the gen to allow the field to be energized. Separate from the light circuit but on the same shaft of the switch. The voltage regulator replaces the wire to the light switch with a real ability to choose charge rate automatically. The numbers on the cutoru (mounted on the generator) will tell all. Or you could take the cover off. If a cutout, it will have one set of windings and contacts. If a voltage regulator it will have two of those relays. The box looks the same. Jim
 
Also do you have a mag or a dist so get a harness for that also you should also get a wiring dia thats in the owners manual so you will know how to install it. Make sure whrn you order you get the correct one some replacement harnesses leaves some things out. Quality and complete makes some of them on the market a not good replacement. good ones will run around 100 or more.
 

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