OK, I had issues with alternator for awhile. The voltage would be at 10 volts when starting and slowly drop to 8 volts after running. Figured alternator because when when measure withm eter at battery, was only reading 12 volts and it would slowly drop. Tested alternator and tested bad. Replaced. Ran good for week, then same thing. Another bad alternator. Replaced. Checked codes, 1682, 0622,0500,1765,1693, 0501. Figured the pcm isn't seeing whati t needs to see to turn on alternator. I installed the external VR to the firewall, after sandig the paint off (good ground). Wired the blue wire to the Vr, top post, to a switched hot when key is on and added a wire to run to the altenator. Ran the green wire to the other alternator post. Cut the original pigtail from the altenator and crimped in the new wires. Taped off the two old wires and left them. Start he truck, after I charged the batteries to full. TRuck starts and idles at measured 14.8 volts to batteries. Gauge reads 10 volts, slowly climbing to 14 volts, then climbs to 18 volts and check gauge light comes on. When it hit about 16 volts on gauge, the lights start to flicker up and down and there is a noise from the motor raising and dropping. All this time the measured voltage at the batteries is 14.4-14.8 volts. Scan gaugeII verifies 14.8 volts throughout process and never changes. What next?

2002 dodge cummins, auto, 4x4.

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Heading out now to ensure the trucks even starts and check the voltage at External VR and at batteries. Might take out batteries (Optima red tops) and have them tested. They are only about 4 years old. Maybe check the connections? At this point I am not quite sure which way to go and what to check. I thought by installing external VR, I would be bypassing the cam sensor and the pcm for alternator control?

I just replaced my pcm with a reman one, programmed with my vin, mileage, etc... I removed the external VR and wired everything back to factory. The voltage is back on line where should be. Everything seems to be running as it should. I still have the 0622 code and the 1765 code. Maybe they will go away after a few key cycles or warm up cycles? I left the grid heaters unhooked for now and will monitor. Mike, what does it take for the truck to erase the codes itself?

Has anyone else run into this issue? Having the exact same problem with a 2001 3500 5 speed truck. It's the service truck at the farm I work for... Literally the exact same situation...Thanks!Will

If anyone else has this issue, swap to a ford style regulator, it fixes the headlight flicker, the radio noise and the overcharging all at once.The ford regulator modulates the power to the field instead of the ground, it also senses voltage from the 12+ post on the alternator and has a separate turn on lead. Wish I had done the ford regulator from the beginning.

I just replaced my pcm with a reman one, programmed with my vin, mileage, etc... I removed the external VR and wired everything back to factory. The voltage is back on line where should be. Everything seems to be running as it should. I still have the 0622 code and the 1765 code. Maybe they will go away after a few key cycles or warm up cycles? I left the grid heaters unhooked for now and will monitor. Mike, what does it take for the truck to erase the codes itself?

40 warm up cycles to self erase codes. I would personally just erase the codes with a OBDII code reader and take it for a test drive and then check again to see if the codes returned. If so then you'll have to deal with the codes.