Not charging with headlights on

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Dartsun

Dartsun

Mopar Dude
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Hello all I have a 65 Dart 273 with electronic ignition and voltage regulator dual field alternator. When I flip my headlights on my ammeter goes to discharge even while cruising down the highway. Do I have a loose headlight ground or bad voltage regulator? Charges fine until turn lights on, just stock headlights nothing special. Thanks Dustin
 
I would check for voltage drop in the harness,clean grounds and lastly add some relays to those lights you wont regret the relays at all.
 
I would clean the battery terminals, and not just the posts, but also where the cables enter the clamps. Then clean the terminal at the starter relay where the power take off point is to go into the car. Then the engine ground. Then the ground strap from the engine to the body.And finally from the radiator core-support back to the battery. Then I would check the battery fluid level,and put the battery on an automatic trickle charger for 2 or 3 days. Then I would clean the regulator case and it's mating surface.
Then I would do a full-field test on the alternator.
If you still got problems, then we will really have to get into it.

Of course it could just be a shorted bulb.You would have to unplug them one atta time, and leave them out. If all the bulbs are out, and no difference, then we will really have to get into it,lol
 
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Speaking of the bulbs... and this is OEM sealed beams with 3 male lugs attached on the back. I once found a lug snapped off a bulb and touching the lug beside it. The short/cross feed was powering high beam and low beam, 3 out of 4 anyway, at the same time, all the time. After discovering the fault, I learned that this car had been in a fender bender. The body man didn't notice this little fault. He wasn't supposed to.
Our old Chryslers have so many typical charging system issues that we pretty much assume the typical culprits, amp gauge connections, firewall connections, etc... Story above was just to say other not so typical culprits are possible.
In this case I would first test the alternators output or have it tested. Might be just a bad diode or something. Good luck with it.
 
One way to test the voltage regulator is to use a voltmeter. With the engine running first test for ground at the regulator, this is done by measuring the voltages with the black lead on battery (-), to regulator case. If voltage is near zero good. Ground is very important, it happens via mounting screws. It is also good to check voltage at engine, body, and alternator case to insure they are all grounded, this means when measuring between them, the voltage is near zero. The test continues below.

Since the alternator and regulator have been upgraded, there is uncertainty in the wiring, since the wiring is different from the original. That you call dual field is really, single field with two connections. The early alternators connected one to the case, the other was driven by regulator. The newer brings both terminals out, one is the powered when ignition is on, the other is pulled to ground to complete circuit by regulator as necessary to regulate. The original powered the single field wire via regulator fron (IGN), again wiring is different. Searching topic and wiring diagrams may help.

The regulator has three connections, ground (case), IGN (Blue), and FLD (green). The (IGN) Blue wire voltage should measure about 13.8V with engine running, and the battery voltage should read very close to that too. If the battery voltage is higher by more than a few tenths there is likely connection problems at bulkhead terminals. By searching this form there are countless posts on the problem, trouble shooting and fixing related problem.
 
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