Automotive Alternator with External Regulator Light stays on all the time

[John1397]

My problem started when I took my alternator apart to grease bearings when I put it back to together dash light came on so took it apart seen wire to one of the brushes was broken soldier back together

it work for a short while the light was back on seen soldier had broke again so I changed the brush assemble now the light was still on so next I installed ammeter between alternator plus terminal and wire to battery with engine idling it puts out a few amps when speeding up engine to high RPM's alternator puts out maximum amps and with battery charger hooked on at same time it still seems to put out maximum amps no regulation and light is on.

Next I changed the voltage regulator from another vehicle same thing no change then I switched the alternator it self no change so this seems to me to simply rule out regulator or alternator so I checked the wires that go to field and regulator on the alternator the both conduct so they are not broken and they are not shorted together

I can't find no problem cause I don't know what to look for. I do not really understand which one regulates I always thought you short out the field this cause alternator to full charge but what does the regulator terminal do as they both go to regulator then brown wire seems to go to lamp but I can't find this on the diagram

but seems to be other things connected to this brown wire and I do not know if the lamp is always grounded or it always connected to positive but I do know that with the brown wire disconnected from regulator alternator will not charge .

I also do not know if the light is suppose to burn with the alternator charging full amps.

So what I have is a lamp that burns all the time, and an alternator that does not regulate. It just charges at full amps. This after changing both regulator and alternator and checking the wiring from the alternator to the regulator.

 

[ChemAir]

I'd suggest having the alternator (and regulator) tested, and change out both the voltage regulator and alternator at the same time. I would also have the battery tested. I have had cases where a damaged alternator hurt a voltage regulator, and vice-versa on a couple of late 1960's Fords, and a marginal battery will have you chasing your tail. If you can find a 1964 shop manual for that car or its Chevrolet counterpart, it may give you a troubleshooting procedure that will be more effective at identifying the source of your problem. It may also tell you things NOT to do.

Also, if there are a large amount of added accessories (lights, fans, fuel/water pumps), your alternator may need to be higher capacity.

I'm sorry, but I can't read the color labels on the diagrams you posted.

 

[chemisttree]

Dis you also replace the diodes?

 

[Tom.G]

Connect your voltmeter (-) lead to the battery (-). Use a clip lead or length of wire if needed.
Make sure the regulator frame is Grounded to the vehicle

1. With the engine Off.
   • There should be battery voltage at the regulator Red wire
   • The regulator frame should measure Zero volts
   • The White wire should measure Zero Volts
2. Use the Ammeter to measure current thru the heavy Red wire on the Alternator.
   • There should be Zero current. If there is current the alternator needs service, either a shorted diode or something else shorted internally.
3. With the engine Running, measure the voltage on the terminals that the White wire is connected to at both the Alternator and at the Regulator. It should be the same and may vary with charging rate.
4. You can get an idea of the battery charge status by measuring its voltage. Fully charged will be a little over 14V.
   • If it is much above that, disconnect the Dark Blue wire from the Regulator. The voltage (and charging current) should drop.
   • If it does NOT drop, the Alternator and/or Regulator has a problem. Leave the wire disconnected and Ground the Alternator connection for the Dark Blue wire. If the voltage/current still does not drop, I'm out of ideas!

The Dark Blue wire between the Regulator and Alternator is the connection to the Alternator Field winding. When the regulator senses a fully charged battery this will be at Zero volts, connected to Ground inside the Regulator.

When the battery voltage is low, the Dark Blue wire will be energized at some voltage to enable the Alternator.

You can also test the Alternator and Regulator by monitoring the battery charging current and its voltage. If the current is low at the battery when charging immediately after starting (a partially depleted battry), there is either a bad connection, or the Alternator and/or Regulator has a problem.

Another clue is if the headlights dim at idle and brighten at higher engine speed, that often indicates a failing battery, or sometimes bad brushes in the alternator.

If all of the above don't find anything wrong and the battery voltage is good, there may be a problem in the dashboard. A bad connection here can sometimes cause the red Charge Lamp to come on when it shouldn't... usually not a Do-It-Yourself project.

Have Fun!

Cheers,
Tom

 

[jack action]

Everything you need to know about GM charging systems from the 60's can be found here:

http://www.madelectrical.com/electrical-tech.shtml

 

[chemisttree]

With the engine Off.

1. • There should be battery voltage at the regulator Red wire
   • The regulator frame should measure Zero volts
   • The White wire should measure Zero Volts
2. Use the Ammeter to measure current thru the heavy Red wire on the Alternator.
   • There should be Zero current. If there is current the alternator needs service, either a shorted diode or something else shorted internally.

We used to measure this current while the engine was on. If there was a significant AC component (needle swings positive and negative) one or more of the three diodes was bad. It would show as an alt light.

 

[John1397]

I found the problem some thing caused the switch in the regulator to bend up (looked like got hot) this way the relay pulls down but switch still open and then light burns and alternator charges full amount when I pushed down to close switch light went out and regulator starts to work strange.