Posted by Sherman in Idaho [24.32.202.166] on Thursday, April 18, 2013 at 12:17:07 :
In Reply to: Re: OT but MOpar posted by Kaegi [24.16.253.154] on Thursday, April 18, 2013 at 11:41:23 :
Let us know what you find. The "one bad diode" situation is the most maddening one to me, because it's really hard to track down with simple measurements. Basically my troubleshooting procedure would be this:
Rev it up enough to show a high charge rate and check to see that the battery voltage is appropriate for that charge rate (i.e. more than 14 volts). If the battery voltage is low, you probably have a bad battery with a shorted cell.
With the engine running at a speed you think should make it charge, check the field voltage. If the regulator is putting full voltage on the field, but the alternator isn't putting out any current, the alternator is bad. If the regulator isn't putting any (or much) voltage on the field, the regulator is bad. From what you've mentioned, I suspect the regulator is okay, but they can fail in lots of different was, so you never know. If it's mechanical, at least open it up and see that all the contacts open and close. A quick test I like to do force the contacts closed by hand and see what happens to field voltage and charging current. There's also nothing wrong with bypassing the regulator at idle speed, by running a wire from the battery straight to to the field terminal to see if that gets it to charging (you'll notice right away because the engine will slow down). If that happens, again the regulator would be suspect.