Chylin73

Just started dealing with this issue and I am glad I came here. 2007 Sierra classic 5.3 190K miles on it and my truck just started doing this last month. Had the battery tested and the machine said to replace battery. Battery was 8 years old so I didn't think anything of it. I put an Optima in and it was holding 14.4V when truck was running so all was good. This lasted for a week then the Voltmeter on dash started showing the drop to about 12.6. Ran thru the typical tests of checking the Alternator and it was doing its job. So I thought maybe the regulating circuit was going bad. I came here to see if anyone else was having this issue and I see they are.