So I had a subwoofer in my truck 2011 gmc sierra 4.8l v8 seirra nevada edition

The battery was becoming pooched so I removed system and replace battery. Voltage started going haywire so I replaced the alternator. That didn't do it so I replace the Battery current sensor on the ground cable off the battery that goes to frame and block that didn't do it. Cleaned all my grounds and cables and everything and that didn't solve it.

After current sensor was replace it did do really well for 20mins no issues a steady 14.2-14.4v and then on the highway when I started acceleration heavily it came back.

I'm not quite sure where my issue lays.. people say pcm ground wire but every video I see shows it in a certain location and on my truck it'* not there, is this because its seirra nevada edition? It is flint Michigan vehicle and I'm in ontario canada.

Any help is greatly appreciated I heard if u basically out of money and idea'* sometimes the forums can help.

Taking it to a shop and bending over in not currently an option rn so please no one suggest that I do the shop route. I'm well capable I just need to know what it is that I'm fixing. I can't simply afford to replace everything electrical on my truck.

Define 'fluctuations"?

hey thank for reply after scratching my head for days now and replacing ground strap and current sensor. Turns out it was my refurbished alternator I bought from RockAuto. Last time i shop there..

My old alternator was fine thankfully I kept it, will try to get refund.

My voltage would go from 10.9v to 17.5 while driving. Lights and electrical had mind of it'* own. Throttle response and everything was affected by alternator. Should never buy refurb that'* a lesson

Weird indeed. What brand reman was it?

Thanks for updating this.

It was called Pure Energy. Suppose to be OEM remake of DR37. Paid a little more for this one if I recall but I was still 150$ more away from brand new. Didn't need anything but a battery but because I replaced both at same time I couldn't figure out my issue. Lol hindsight is clear as day. No one gives a crap about their job. If they tested the alternator after rebuilding it they would of known this issue was present in the alternator. I heard nothing but good things about rockauto but all I've had is issues.

Best of luck to anyone with voltage issues.

Re ignite the thread if anyone needs any help

Probably some minimum wage teen sitting at a test station all day that didn't have a clue.