Alternator hookup

• Wiring Harnesses

Sure, if its a "one wire" alternator and most require Negative ground you know, you could indeed simply wire the alternators output post up to the battery and it would charge it and you can feed lights etc off the hot battery post with a fuze and switch etc

HOWEVER dont you have an ammeter?? If so and you want it to work correctly, the alternators output plus feeds to any light switches would be wired on the Load side while the ammeters other Supply terminal (only 1 wire there) would be what wires to the battey, often at the big battery cable connection on a switch or solenoid.

Then if you use a one wire alternator and youre at negative ground (like most all are) youre good to go. Buttttt t like Bob noted and most of us prefer the 3 wire GM 10 SI configured to work as a one wire cuz they are cheap n readily available and they excite at a lower RPM and theres no problem of any trickle discharge. With that on a diesel you gotta do some more wiring, however to power up the excitation circuit.

Bob's pics and Bob M's diagrams can get you wired, (not sure if they show how to wire an oil pressure switch for the excitation circuit on a diesel???) I do it a little differently but either way will work.

John T

MOST alternators are 12-Volt (-) ground, but like everything else, there are exceptions.

A common alternator for 12-Volt systems is a 10SI Delco, shown here:

You can connect it up, using a diode, as shown, or a #194 lamp "idiot light" in place of the diode. They are COMPLETELY interchangeable, and you can use either one you choose.

Bob Melville, over on the IH board has drawn up, and graciously made available, a series of wiring diagrams.

No matter WHAT color tractor you are working with, there will be a diagram that will work for you, with little or no modifications.

One of the diagrams, good for a diesel, shows how to wire in a oil pressure switch, since a diesel MAY not have a key (ignition) switch.

Oh, yeah, it is REALLY simple to wire up a "3-wire alternator, as shown. Do yourself a favor, and don't even THINK about getting a (goofy) one-wire alternator! The "one-wire" alternators typically are more costly, more prone to slowly discharge the battery during periods of non-use, and usually require the engine to be "revved up" to get the alternator to start charging, at each startup.

• BobM's diagrams