I have essentially answered these questions already:

You can check the wiring by comparing what you have to what I listed in my previous post. That may mean actually checking connections for continuity. Visual inspection is not helpful when it comes to electrical. You will need to put some more detail behind the statement that "all connections are good." Any difference between what I listed and what you have (thanks to a previous owner) must be corrected.

As I said in my previous post, a parts store can bench test the regulator. There are no tests you can do at home to test a later-model electronic voltage regulator without specialized laboratory equipment. While uncommon, it's not unheard of to get two bad parts in a row.

 

FMC, I thought he said the ampmeter was aftermarket .... though I forgot he mentioned the "d to c gage" as he called it (ampmeter).
I know I just plugged the same original 1977 harness connector into the electronic VR back in the 1980s and it's been there ever since. Mine has the original cluster with ampmeter but it hardly moves at all since that change, but it doesn't hurt anything neither.
That I terminal just causes a red light to glow in discharge mode in absence of a gage.
Really, looking at the diagram posted .... seems to me my post was right? Sure, I didn't add all the other stuff that FoMoCo put in the harness (like radio capacitor or amp meter, etc as that's "in the harness"), I sought only to describe the terminals of the VR.

AAP does not bench tests VRs .... they test charging systems on the vehicle if you get it to the parking lot and they can bench test alternators and starters and generators and batteries.

 

Correct, but if it is disconnected (as is the case with the factory ammeter setup), then the keyed signal must run to the S terminal instead. This is necessary to bring the regulator online and "excite" the alternator.

For the ALT light setup, voltage applied to the I terminal (through the ALT light filament) applies a pilot signal to the F terminal of the regulator. As the engine cranks, the alternator turns. Because current passes through the field winding (due to voltage applied to the F terminal) as the alternator turns, a signal appears at the stator terminal. In the ALT light setup only, the alternator STA terminal (stator) is connected to the regulator S terminal. Voltage at the S input of the regulator tells it that the alternator is producing current; it then closes the field relay, shuts off the ALT light and regulates field current into the alternator. Modern electronic regulators do not have a field relay but employ the same functionality.

For the ammeter setup, this mechanism is not used. The stator output of the alternator does not run to the voltage regulator; keyed power is run to the field relay coil (S input) directly. The regulator is online anytime the key is on, and the alternator is excited as soon as it begins turning.

Your post was incorrect. Please refer to the disclaimer I added when I referenced the diagram:

Both the ALT light setup and ammeter setup are consolidated into the single diagram. However, the two setups are mutually exclusive. Not all connections in the diagram are installed at the same time; in several cases it labels connections as specific to one setup or another. The connections to the voltage regulator are different between trucks with an ALT light or an ammeter; the connections you stated are specific to an ALT light setup and do not apply to the OP.

 

FMC I went back through and checked for continuity through the wires and got nothing, started tracing wires back and finally realized the wires were in the wrong places on the regulator, switched them back around and everythings working fine now, old regulator works fine as well, just have to figure out who was ignorant enough to mess with my vehicle

 

Glad to hear you got it worked out.

 

OK FMC .... I see where we got hung up. My way would work to awaken the VR so it would excite the alternator .... but you're saying there's no need or desire to run that wire from S to STA on a truck with ampmeter as it get's power to the S term through the switch in the factory harness .... and I agree if it's getting that signal.

He said his wiring was a mess, I don't know what or how bad that is. In part I was focused on some notion of a wiring mess.

Yeah, because they changed the wiring to run an ampmeter and removed the direct connection S to STA .... I thought that you were trying to tell me a wire from S to STA wouldn't work.

Unlike mine, he said his wiring is already a mess. If he does use a electronic VR (and rely on a voltmeter and just forget the ampmeter ... just leave it be) .... a wire running from S to STA would do it in absence of switched power at S.

If his wring is not a mess and the plug still there .... ground a good electronic VR and then plug it in like I did. In this case, where there is switched power at the connector that slips on the S terminal there would be no reason or any desire to run an additional wire to the STA terminal as well .... (one or the other .... not both).

 

No, when I quoted your post I stated that the connections you listed (including the connection between the alternator STA output and regulator S input) applied to an ALT light setup (and only the ALT light setup).

If you want to do it this way, then you must also apply power to the I terminal of the regulator. The stator will not show signal as the alternator turns unless there is field current. For there to be field current before the field relay closes, power must be applied to the I terminal.

To summarize: you may apply keyed power to the S input of the regulator, to bring the regulator online as soon as the key is on. OR, you may apply keyed power to the I input of the regulator AND connect the STA output of the alternator to the S input of the regulator, to bring the regulator online once the alternator actually starts charging.

Not only is there no reason to, there actually is reason not to, as doing so in this case would short the alternator stator to its output windings through the ignition switch. As you correctly point out, the connection is either-or, but my point is that there is an AND that goes along with one of them.

 

FMC when you say there must be power applied to the I terminal, what do you mean by that? What would happen if there weren't power applied to it?

 

You do not need power applied to the 'I' terminal in your case because you have the ammeter setup, which is wired differently. There is nothing to worry about. Your 'I' terminal should be disconnected; it is only used for the ALT light setup.

 

Not sure if it's related to the over charging problem but since them my turn signals don't work, I replaced the flasher still nothing, haven't had a chance to check the bulbs yet, but the turn signals/front running lights are completely out at all times, the brake lights/rear running lights work fine, could something have been fried when the alt was full fielding?

 

It's likely unrelated. Check the bulbs first.