Yet another charging system thread.

[WorkinLonghorn]

SOLVED I left my lights on for 2 hours the other day (with highbeams-4 bulbs shining). When I went to start it it started but I noticed that the ammeter was not showing any charging. I just figured one of the little fuses in the front corners had blown, but no, my battery continued to run down and I was seeing <12v at the battery with engine running. This is a totally standard stock set-up with a newer regulator and alternator. I took the Alternator down to AutoZone and it tested good, twice. I substituted two other regulators that I had on the shelf of questionable condition. Still nothing.

I have 12v at the red wire both alternator and regulator but the only other voltage detected was with key on engine off one of the two wires in the plug going to the alternator (black in my case) which shows ~1.5v. Nothing on the Regulator connection other than the 12v red as mentioned.
Tomorrow I plan to check the brown wire again and see if there is a wire off at the ign. switch because I read in a thread here that the brown wire should be energized with key on and it is not.

Am I on the right course? Thanks! -Brian

[RichardJ]

Check the battery.

>> <12v at the battery with engine running.<<

What's the voltage at 2000 rpm? The 10 DN isn't capable of putting out a lot at idle.
Try putting a full charge on the battery with a charger and checking battery condition. Clean battery posts.

[tdangle]

I believe that even with a external regulated alternator at the plug you should have ground on 1 connection and +12V on the other to excite the field coil that in effect becomes a electromagnetic. The 12 V at the terminal is being fed from the battery. The external regulator gives 12V to the alternator to turn it on. Double check the wiring going from the regulator and the alternator and also i believe you should have 12V from the ignition switch to the regulator In the electrical section is posted a wiring diagram.

[WorkinLonghorn]

Originally Posted by RichardJ

Check the battery.

>> <12v at the battery with engine running.<<

What's the voltage at 2000 rpm? The 10 DN isn't capable of putting out a lot at idle.
Try putting a full charge on the battery with a charger and checking battery condition. Clean battery posts.

12.25 at the battery running at any speed. I've had this truck for 22 years and I know how it should perform and even at idle I should have ~14v.

Thanks, Brian

[WorkinLonghorn]

Originally Posted by tdangle

I believe that even with a external regulated alternator at the plug you should have ground on 1 connection and +12V on the other to excite the field coil that in effect becomes a electromagnetic. The 12 V at the terminal is being fed from the battery. The external regulator gives 12V to the alternator to turn it on. Double check the wiring going from the regulator and the alternator and also i believe you should have 12V from the ignition switch to the regulator In the electrical section is posted a wiring diagram.

OK thanks, will check into it tomorrow.

[Ironangel]

Make certain that the voltage regulator is grounded to the radiator support and that the alternator is grounded to the engine block. The regulator is mounted in rubber grommets
so it should have a wire connected between it and the support. The alternator is grounded through it's case mounts brackets to block. Engine should be grounded directly to battery. This might help http://67-72chevytrucks.com/vboard/s...d.php?t=406264

[WorkinLonghorn]

Originally Posted by Ironangel

Make certain that the voltage regulator is grounded to the radiator support and that the alternator is grounded to the engine block. The regulator is mounted in rubber grommets
so it should have a wire connected between it and the support. The alternator is grounded through it's case mounts brackets to block. Engine should be grounded directly to battery. This might help http://67-72chevytrucks.com/vboard/s...d.php?t=406264

Thanks, I'll double check. It worked fine before I left the lights on though. The regulator is mounted directly to the metal, no rubber any more. I'm more concerned with which leads should be energized that are not.

I think I am seeing my answers here; http://67-72chevytrucks.com/vboard/s...d.php?t=734619

I didn't see this yesterday during my searches.

[WorkinLonghorn]

Was the little wire coming out of the Ign. Switch to the regulator. Thanks VetteVet for your posts in the above referenced thread. -BA