Electrical System

[msass]

New to the forum. Seems like a great place. I'm having some issues with my electrical system. The generator was bad so I replaced that, also replaced the regulator. The first time I drove it everything seemed great, then on the return trip home the amp light came on again. Once it is started it runs great. Any ideas as to what might be causing that light to stay on? Bad wiring?

[kaiserfrazerlibrary]

There are a number of possibilities as noted in the factory Shop Manual for the car.    Generally, the GEN light actually goes on if current drops below a certain point.  It is not unusual for the light to flicker or go on at idle depending on idle speed.  This is listed in owner manual as well as the shop book.

Critical factors here are Voltage Regulator condition and settings and wiring.  6 volt systems take a lot more current than 12 volt and are more sensitive to corrosion, general deterioration and even tightness of contacts.  All these things happen as a normal result of aging and how the car was previously stored and used. 

Also, do you have the Auto-Lite or Delco-Remy electrical system?  I assumed you replaced your bad generator with another of same brand.

[Fid]

Just to echo, it is typical for the AMP light to be on at idle, especially with the Autolite equipped cars and especially at night if  you have the lights on. If the light is only on at idle, you're likely OK but if it comes on and stays on while driving then yes, check the wires/terminals for corrosion.  I've also seen bad regulators out of the box, especially new ones. I had one that was putting out 9 volts! If you have a meter, check it and see what it is putting out.

[retired wrench]

  Regulators are adjusted at the factory under ideal conditions,thats all they can do. When you put them on a car with old wiring,corroded connections,or a sulphated battery they can be way off. Not to say this is the only thing that could be wrong, but a possability.

[Fid]

One other thing we should mention just in case... I don't know if you're aware but KF cars were all originally Positive Ground. If you hook the battery up the other way and don't repolarize the regulator that may cause problems. Having the battery connected as Neg ground won't cause any immediate issues, however, over time the regulator can burn up if it is not properly polarized.  You may know this but I am stating it so it is not a case of overlooking the obvious.

[msass]

It stays on when I am driving it, it will go off if I rev it up at idle. Is it possible the regulator isn't quite set correctly and I'm just not quite getting enough volts during idle or normal driving? It is putting out just over 6 volts. I have everything as positive ground.  Thanks for the advice. I will keep working on it.

[Corsairdeluxe]

Read this through a couple of times.

http://www.stinsonclub.org/PublicTech/YahooGroup/DC%20generator%20theory.pdf

[msass]

Is it possible that the light would be on if my battery is just really bad?

[BigDave LM6174]

Yes.  How old is your 6 volt battery?

[joefrazer]

Is the belt tight? What you describe is a symptom of a loose fan belt.

[kaiserfrazerlibrary]

Check the diagnostic in the factory service manual and read the material in the ELECTRICAL section on the charging system.  If you don't have a factory service manual for your car, you should get one ASAP as a service tool, along with the parts book.  The service manual that's best covers 1951-53 HJ and will also work just fine on 1954 models.  The Parts Book that's best for any year HJ is the 1951 green cover illustrated book with the 1952-53 supplement (which also covers 1954 except for hood ornament plastics). 

Club members will get a scan copy of the supplement in KFOCI HANDBOOK Version 5.0 when it comes out later this year as a QUARTERLY issue.  It is available to members getting publications (sorry, Associate Members don't get publications) and is not sold by the club to non-members, or at least that's what was done with Version 4.0.  It goes out to new members with their New Member Packet.

[msass]

Belt is tight and the battery is only a couple years old, but it has been charged up and run down many times while trying to figure all of this out. Also wondering if I need different battery cables. 1 gauge?

[joefrazer]

The original cables were zero gauge to the starter and a braided unit to ground.

Two good videos that explain how to test a generator and a voltage regulator. Both deal with 12V MGs, but the concept is the same.

http://www.youtube.com/watch?v=noK-oZMb8i8

http://www.youtube.com/watch?v=tSJxCNLgL2w

Good article that explains some in-car testing that can be done -> http://www.vintagejeepparts.com/PDFs/INSTRUCTIONS%20FOR%20INSTALLING%20VOLTAGE%20REGULATORS.pdf

[Fid]

You may want to retrace the wires from the generator to the regulator.  I once got the field and ground wires swapped by mistake. This results in the field being grounded all the time so no regulation takes place. It will put out more voltage than required and the light will come on as you accellerate. This did wreck my battery as it was over charging.  The old wires that are faded are easy to get mixed up.

[msass]

Wires are the next step. I've driven it after charging the battery and if the RPMs are high enough the light goes off. As long as I stay on the gas even a little bit the light is off, but as soon as I take my foot off the gas it immediately comes back on until the RPMs get high again. Does that help anyone at all?