'66 Chevy Alternator Wiring

[Glenn F.]

The fun continues with putting together a slightly cobbled wiring
system that I did not take apart.

Today's question: The plug that goes into the alternator has a
blue wire going into it, and a short red wire sticking out of it
(so plug currently has only one functioning wire). The short red
Eire has a loop on the end of it. T could nicely reach out he
terminal on back of alternator that says "battery", but somehow
that doesn't seem right to me. There is another red wire in the
"loom" with the wire with the plug which I assume goes to the he
terminal marked battery.

Where does fat red wire coming out of the plug go?

Sorry for the wordy question.


Glenn F.

 

[Glenn F.]

It could nicely reach the terminal in back of the alternator...

Phone thinks it's smarter than me.


Glenn

 

[Dalex]

You are right , the short red wire goes to the Bat. terminal on the alt.

 

[Mike M]

Does that alt. have the plug in the back or on the side ?
Originally that car would use the one with a plug in the back and those wires run to a voltage regulator mounted on the radiator support or fender ???
Someone could of put a later style on it with a built in regulator ?

 

[Glenn F.]

Plug is in the side.

 

[Glenn F.]

Could that second red wire (that goes to the battery and then around front of radiator to ampmeter?) also mount to that terminal?

Sorry to sound so stupid.


Glenn F.

 

[old]

In the side as in the round part of it?? Sort of flat looking not square?? If flat that is a later model 10SI and can be wired like it would be if you where putting it on a tractor. Has a #1 and #2 on the alternator and the #2 wire goes to the charging stud and the #1 is the excite wire and that goes to the ignition switch the side that is switched

 

[Glenn F.]

Hard explaining in print. Battery stud is in back of alternator, facing firewall. Plug is in the side of alternator, very close to back, in the area with horizontal lines/grooves cast in the housing. Looking from the front the plug is in about the 10:00 position.

Glenn F.

 

[Allan in NE]

If it's the original unit, the blue wire goes to one side of the idiot light and the red to "hot" via the ignition switch.

Allan

 

[Allan in NE]

Never mind, should have read the whole thread.

Allan

 

[Steve@Advance]

Sounds like it's been upgraded to a 10SI internal regulated alternator.

The terminals are numbered:
#1 goes to a resistor then to the ignition side of the ignition switch. (Google 10SI alt wiring)If its not wired for the resistor, you can wire in a diode, or series an instrument lamp as a resistor. This is to keep the alt from feeding power back to the coil when you turn off the ignition.

#2 loops back to the "BAT" terminal on the back of the alt.

The "BAT" terminal goes to the ampmeter.

PS: Got to thinking about the starter wiring... If you are going back with points, it will be right as it is. If you go with HEI distributor, you'll need to wire around the ignition resistor. Other aftermarket electronic ignitions may or may not use the resistor, follow their instructions.

 

[old]

If the plug in plugs in parallel to the shaft/armature then it is the old type and has an external regulator. If the plug goes down and would be at a 90 degree angle of the shaft then it is a newer 10SI

 

[Glenn F.]

Okay. It's the newer one. Thanks Old.


Glenn

 

[old]

So you can wire as I said in an earlier post of mine then. If you search the archives Bob has posted a picture of how it looks and is wired so if you can find that it may help you