Voltage regulator to field wire up in smoke

Lets start at the beginning...

72
Dodge
Charger
318


What modifications have been done to the car (especially in the engine compartment, under the dash and to the electrical)

Where did the smoke come from ( under dash in the engine compartment?)

do you have a wiring diagram?
mymopar.com
classiccarwiring.com

Watch this video



You should have an electronic voltage regulator. The way they work is one wire with full battery voltage (Blue?) goes to one of the field terminals on the alternator. Another wire (green?) from the other field terminal goes to the voltage regulator where it goes through circuity to produce a variable ground to very the field strength to modulate the output of the alternator.

If the alternator was changed recently the wrong year alternator may have been put in. older cars (69 and older????) used a ground field alternator. Rebuilders are short on round back alternator cores and use a square back core but they ground one of the terminals to convert it to be a functional equivalent to a round back.

to test the alternator remove both field wires and check for low numerical ohms on each field terminal to ground. any reading other than "OL" or what ever your gauge reads when both leads are not touching each other indicates the alternator might be bad.


you said the blue wire is fried, from where to where? can you see its entire length?

if it is in a wiring harness and it melted / fried it is very likely that other wires in contact with it are also fried.

What ever happened suggests you have a direct short somewhere. if you have an electronic choke look at that wire as it might have fallen off and is shorting to the Manifold

you will have to trace out the problem there is no magic bullet we can share. every failure with these old cars is unique to your car.

good luck

Thanks and you are right that it is the blue wire and and the alternator is a square back but my old man said he never did any modifications or had to change any components before he passed and left me the car 6 yrs ago. I've never had to do any part swaps since I've had her other than regular maintenance and a drive around the block so she doesn't sit for too long.The blue wire is in a harness basically the entire length of the engine but it was melted at the alternator and I could see smoke coming from the blue wire at the ballast resistor and at the voltage regulator which also got hot as it looked like she was smoking (not 100% sure on that because it could've been the wire attached to it). Only smoke was coming from engine compartment. I will replace the blue wire and will get a good look at the rest of the harness while I'm there.. I thank you for the wisdom and will proceed to bench test the alternator. As far as electric choke.. not too sure about that as I don't know much about these older cars like that. How can I (bench)test the regulator? Oh picture for reference of the blue wire route (not my car fyi)

1972-Dodge-Charger-SE-Brougham-3-e1645829280305-630x390~2.jpg