So I'm getting a "Battery Not Charging" message on the dash. I check the voltage at the regulator and its only outputting 3v. When I unplug the PCM connector it puts out 10-11v.

I replaced the alternator and get the exact same behavior.

After about two hours of driving, the battery is dead. It's the night before Thanksgiving and I'm stuck in a ratty hotel outside of Atlanta with a charger on my battery. I have two more hours of travel and then the return trip.

When I pull the codes with my BlueDriver I'm getting a P1638 "During the ignition on test, the PCM detects a pwm out of range." I've been doin some rewiring so I'm sure its a ground or fuse issue. I'll have time to diagnose it when I'm home. For now though, is there a manual way that I can switch the alternator to send the full 14.4v charging voltage?

This is the H2 so ground to body, main output to battery+ then there's the two wire control connector. There's an AC Delco up the street. Can I buy an alternator connector and straight wire the two wires directly to? What? Battery pos/neg with a switch and voltmeter?. To themselves? Can I basically hardwire the connector in some way to put out enough voltage to charge the battery?

ANY help would be much appreciated. Just tryin ta get home...

 

So, just for future reference, this alternator: DR44G needs a signal frequency of 191hz to putout14.4V.

With an Arduino [ connect wire (when connected to the alternator from the driver's side):

Wire: 2 (furthest away from the driver side what would be the yellow wire from the original connector) loop back around to the alternator + connector
Wire: 1 (closest from the driver side what would be the brown wire on the original connector) to the alternator connector to pin 9 of the Arduino and use the sketch at: https://pastebin.com/ciNEfhtU

This will send a constant signal of 191HZ to the voltage regulator which will force the alternator to output 14.4V

P.S. Arduino's should be in your Hummer toolkit, since every single fricking thing works via single and not just analog 12V

 

Arduino:
Alternator connector:
(connect is twice the price of the Arduino which says a lot about ACDelco)