Jesnic

Going over grounds now. Replacing battery connections with new and then on to grounds. - - - Updated - - - New connections on batteries. Batteries, unhooked voltage = 12.5 volts. All grounds intact. Ohmed from alternator body to neg batt= grounded. Body to engine= grounded. Started truck. Voltmeter on battery reads 14.7 - 15.0 volts on both batteries. Scan gauge II reads 14.5-15.0 volts, steady. Gauge in truck took a few minutes but ramped up to 18 volts and stayed there with check gauges on. Lights still pulsing. AC voltage at batteries = .028. What else could possibly be going on? Mike, you around? - - - Updated - - - Ok, mistake on ac voltage at batteries. DC voltage = 14.7 volts. AC voltage = 167.4 milivolts. When the guage ramps up to 18 volts, inside the truck and the check gauges light comes on, the DC voltage at batteries is still reading 14.7- 15.0 volts, but the AV voltage goes up to 200.6 millivolts. Any suggestions?

The run up to 18 volts happens long after the grid heaters have cycled. It happens after the trucks has run for 20 mins and going down the road at 45 mph. It doesn't drop back down until I shut it off and start it again, then the same thing. I would theink that maybe the gauge is bad, but the lights flickering and the motor sound leads me to believe that the voltage increase is real somewhere in the pcm or ecm.

I bought the VR that mopar man suggested. Just not sure why the Vr will put out the correct voltage, but the truck gauge maxes out and flickers lights.

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. - - - Updated - - - 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?