Not charging with headlights on

First I have the 69/older system with only one GREEN wire field, so do I do the same testing with two fields?

67Dart273
could you direct me to a correct way of testing my alternator, regulator.
Thank you.

You said something about "green not connected." It won't charge with the green disconnected. If you read the test procedure carefully, the gist is that you need to unhook the green, and clip a wire to the field terminal on the alternator which you just unhooked, and hook that wire to a battery source to see if it's charging. Many guys call this "full fielding" which means that instead of the regulator feeding power to the rotor (field) you are now directly doing so with a clip lead.

This eliminates the regulator and a certain amount of wiring.

If the thing does not show a charge on the ammeter at this point, you need to put a voltmeter directly from the alternator output stud and see what the voltage reads while running at a good fast idle. This will tell you

1--if the voltage has gone above the battery, showing charge

2--if the voltage has gone WAY high, showing that the charge line from the alternator output, through the bulkhead, ammeter, and back out to the battery has a break somewhere.

Well I have tested the alternator as you said, with direct cable from battery to field where green cable was connect. With engine off it read the same as battery 12.78v.
Started the engine in idle the reading on the big terminal was 14.4v with engine rev up it goes up above 15v, I think it was the same on battery terminals.
I hope this means my alternator is good.

Connected the green field wire back, taking out the battery link, with engine in idle the reading on the back of alternator is 11.8v to 12.6v and very unstable.

I am going to check the wiring between regulator and alternator next.
I have Ammeter and Voltmeter and both are unstable, anything between 11 to 14v.

Appreciate any help, thank you.

Ok what you did means the alternator is good.

Now you can take it a step further and check the regulator wiring. Remove the regulator, and jumper the two regulator wires together. This, essentially, does the same thing as connecting the field terminal to battery. Run the car long enough to see if it charges.

If it does, double check absolutely sure that the regulator is well grounded, and replace the regulator.

Just wanted to report that with a new regulator everything is back to normal and it charges just fine. Once again thanks for the great input and help, especially 67Dart273.

I've been reading this whole thread and wanna thank all parties involved for great information. I'm new to cars and am having a charging issue with my 73 Dart with a 440. Looking forward to using the above info for troubleshooting my own charging system.

How would you test if the alternator is good, but too small, considering I was told my electric fan pulls 30-40 amps on its own? My alternator is a 60amp

Thank you

You should start your own thread with details of the problem. This thread was geared towards the "old style" (69/ earlier) regulator set up, where yours has the newer (70/ later) set up, sometimes incorrectly called "dual field" but more correctly "isolated field." These are the 70/ later alternators with two field connections.

67Dart273 said:

Now you can take it a step further and check the regulator wiring. Remove the regulator, and jumper the two regulator wires together. This, essentially, does the same thing as connecting the field terminal to battery. Run the car long enough to see if it charges.

If it does, double check absolutely sure that the regulator is well grounded, and replace the regulator.

Click to expand...

I had to change the field wire between regulator and alternator, as wire was hard and braking, also change the regulaotr and now it is all working as it should.

Thank you 67Dart273 for your help on this.
FABO is a great place to find information on these cars. :cheers::cheers::cheers: