Battery Performance Revealed Unraveling Fluctuating Readings Mid-Drive

... and coming back on, no trouble codes and not all the time. I was in the power room today when it happened, the battery voltage drops ... (take it off the truck, your local auto parts store should be able to test it.) If the alt tests good, voltage regulator is bad, which, ... drops to 12.5 while driving ... If it keeps up, then have a FLAPS load test the battery no alternator at RPM you are seeing the fluctuations. This will cause the voltmeter to fluctuate between 12 and 14 volts as opposed to non-regulated systems that usually maintain a more consistent ... Get the battery load tested. Only way to confirm battery is indeed good and not having a weak cell only holding a ''surface'' charge. Short drives are normally a cause of battery/charging issues and so you are not fully charging the batteries. Hence the system charging voltage ... Testing the battery, with the car on (headlights and heater on ... mine fluctuates, startup its around 12.8 for a while until i drive ... Remove the ECU 32 pin wiring harness connectors and inspect the clips and pins for oxidation. The ECU controls the alternator charging rate of ... Nope. That pretty much sounds like a dead battery. It sounds as though one of the cells has a short in it, which is causing your rapid ... As the battery charge is used up the internal resistance does increase (as you mentioned). The result is when you hook the battery into a ...