2014 4.3 Voltage Problem

sheriffjim · October 4

Hello, as the title states I have a 2014 4.3 liter. This is my first post here so I apologize if I do something wrong.

I'm having an issue where I lose power while I'm driving. Sometimes it's the radio, sometimes the dash, AC, power steering, sometimes it's all of these. Sometimes the engine dies. Each time I replace something it goes away for a month or so and comes back worse. When its acting up the AC, dash lights, and headlights will "pulse" and the engine runs terribly. Even the radiator fans fluctuate.

I have already looked at the G218 ground. The insulation was fine and the ground was tight, but I cut away the insulation and put a wrench on the nut to be sure. I also checked the battery cables. The positive was out of spec so I replaced it. Negative is in spec and both grounds are clean and tight. There is no visible damage to the cable. There are no warning lights on the dash.

The alternator is less than a year old but it is a reman unit.

This issue seems to coincide with a drop in charging voltage. The gauge reads low and I measured 12.6 volts at the battery. I know about the economy charging thing. Even with hazards, AC, radio, headlights, and bed light on, turning the wheel back and forth (enough load that the AC and dash would shut off when I turned the wheel), it remained at 12.6 volts. I also put it in tow mode which I heard will force it into charge mode, but that didn't change anything. What's confusing me is that when I turned it off and back on, it went up to 14 volts for a little while and then back to 12.6, and when I tried to load it again it rose to about 13 (so, exactly what it's supposed to do). What's confusing me is it seems to be working correctly sometimes and other times it just doesn't.

Any help is appreciated.